2019年mpacc考试英语真题——名词1136

{01}— Why are you so popular with your students?
— As a teacher, I seldom give my students so difficult a problem ____ they cannot work out.

A.as

B.that

C.if

D.which

解析：考查定语从句。先行词为a problem，后面的从句they cannot work out后缺少宾语，所以使用关系代词，so… as，为固定搭配，所以选A。
本题选A。
{02}When the farmers dug the well, they _____ a large collection of ancient china.

A.came by

B.came around

C.came up

D.came across

解析：
本题选D。