（2011、海南单科、22）日本自民党从1955年开始长期执政，在六七十年代出现表1所反映的变化。导致这一变化的重要原因是，自民党（    ）                <table style="BORDER-BOTTOM: medium none; BORDER-LEFT: medium none; MARGIN: auto 6.75pt; BORDER-COLLAPSE: collapse; BORDER-TOP: medium none; BORDER-RIGHT: medium none; mso-border-alt: solid windowtext .5pt; mso-table-overlap: never; mso-yfti-tbllook: 480; mso-table-lspace: 9.0pt; mso-table-rspace: 9.0pt; mso-table-anchor-vertical: paragraph; mso-table-anchor-horizontal: margin; mso-table-left: right; mso-table-top: 30.95pt; mso-padding-alt: 0cm 5.4pt 0cm 5.4pt; mso-border-insideh: .5pt solid windowtext; mso-border-insidev: .5pt solid windowtext" border="1" cellspacing="0" cellpadding="0" align="right" _dj="MsoTableGrid"><tbody><tr style="HEIGHT: 17.3pt; mso-yfti-irow: 0; mso-yfti-firstrow: yes"><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: windowtext 1pt solid; PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 56pt; PADDING-RIGHT: 5.4pt; HEIGHT: 17.3pt; BORDER-TOP: windowtext 1pt solid; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm; mso-border-alt: solid windowtext .5pt" valign="top" width="75">年份</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: #000000; PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 31.15pt; PADDING-RIGHT: 5.4pt; HEIGHT: 17.3pt; BORDER-TOP: windowtext 1pt solid; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt" valign="top" width="42">1958</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: #000000; PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 33.8pt; PADDING-RIGHT: 5.4pt; HEIGHT: 17.3pt; BORDER-TOP: windowtext 1pt solid; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt" valign="top" width="45">1963</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: #000000; PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 33.8pt; PADDING-RIGHT: 5.4pt; HEIGHT: 17.3pt; BORDER-TOP: windowtext 1pt solid; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt" valign="top" width="45">1967</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: #000000; PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 29.2pt; PADDING-RIGHT: 5.4pt; HEIGHT: 17.3pt; BORDER-TOP: windowtext 1pt solid; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt" valign="top" width="39">1972</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: #000000; PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 37.95pt; PADDING-RIGHT: 5.4pt; HEIGHT: 17.3pt; BORDER-TOP: windowtext 1pt solid; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt" valign="top" width="51">1976</td></tr><tr style="HEIGHT: 18.2pt; mso-yfti-irow: 1"><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: windowtext 1pt solid; PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 56pt; PADDING-RIGHT: 5.4pt; HEIGHT: 18.2pt; BORDER-TOP: #000000; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm; mso-border-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" valign="top" width="75">自民党议席</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: #000000; PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 31.15pt; PADDING-RIGHT: 5.4pt; HEIGHT: 18.2pt; BORDER-TOP: #000000; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" valign="top" width="42">287</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: #000000; PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 33.8pt; PADDING-RIGHT: 5.4pt; HEIGHT: 18.2pt; BORDER-TOP: #000000; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" valign="top" width="45">283</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: #000000; PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 33.8pt; PADDING-RIGHT: 5.4pt; HEIGHT: 18.2pt; BORDER-TOP: #000000; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" valign="top" width="45">277</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: #000000; PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 29.2pt; PADDING-RIGHT: 5.4pt; HEIGHT: 18.2pt; BORDER-TOP: #000000; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" valign="top" width="39">271</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: #000000; PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 37.95pt; PADDING-RIGHT: 5.4pt; HEIGHT: 18.2pt; BORDER-TOP: #000000; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" valign="top" width="51">249</td></tr><tr style="HEIGHT: 18.2pt; mso-yfti-irow: 2; mso-yfti-lastrow: yes"><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: windowtext 1pt solid; PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 56pt; PADDING-RIGHT: 5.4pt; HEIGHT: 18.2pt; BORDER-TOP: #000000; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm; mso-border-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" valign="top" width="75">在野党议席</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: #000000; PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 31.15pt; PADDING-RIGHT: 5.4pt; HEIGHT: 18.2pt; BORDER-TOP: #000000; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" valign="top" width="42">180</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: #000000; PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 33.8pt; PADDING-RIGHT: 5.4pt; HEIGHT: 18.2pt; BORDER-TOP: #000000; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" valign="top" width="45">184</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: #000000; PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 33.8pt; PADDING-RIGHT: 5.4pt; HEIGHT: 18.2pt; BORDER-TOP: #000000; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" valign="top" width="45">209</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: #000000; PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 29.2pt; PADDING-RIGHT: 5.4pt; HEIGHT: 18.2pt; BORDER-TOP: #000000; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" valign="top" width="39">220</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: #000000; PADDING-BOTTOM: 0cm; BACKGROUND-COLOR: transparent; PADDING-LEFT: 5.4pt; WIDTH: 37.95pt; PADDING-RIGHT: 5.4pt; HEIGHT: 18.2pt; BORDER-TOP: #000000; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" valign="top" width="51">262</td></tr></tbody></table>表1  日本众议院席位变化表