单项选择题

Directions :In this section, there are 10 incomplete sentences. You are required to complete each one by deciding on the most appropriate word or words from the 4 choices marked. Then you should mark the corresponding letter on the Answer Sheet with a single line through the centre. Lisa could not find her pencil-case anywhere. Perhaps she ______ it in a hidden place.

A. might have put
B. must have put
C. put
D. had to put