Question

The teacher said he needed _____ boys besides his students _____ the classroom.

1. A.
   20 other; clean
2. B.
   20 more; to clean
3. C.
   20 more; cleaning
4. D.
   another 20; clean

Answer 1

B
another 20 students =" 20" students more；　后面是不定式作目的状语。