Question

The teacher often told me to ________ the good work.

1. A.
   keep on
2. B.
   keep off
3. C.
   keep up
4. D.
   keep at

Answer 1

C
keep up“坚持”，后一般加名词或代词；keep on“坚持做；反复做……”，后边一般加动名词；keep off“远离”的意思．keep一般不与at搭配，故选C．