We _______ turn off the lights before we leave the classroom.

A) and B) but C) or D) yet

A) What B) What a C) How D) What an

A) seldom B) always C) never D) sometimes

A) seriouser and seriouser B) more and more serious

C) more serious and more serious D) more serious and serious

A) badly B) well C) good D) bad

A) all B) both C) any D) either

A) Thousands of B) two thousands C) thousand of D) two thousands of

A) in B) at C) on D) of

A) himself B) he C) him D) his

A) a B) an C) / D) the