Question

Our English teacher is now busy ________ for the exam.

1. A.
   to prepare
2. B.
   preparing
3. C.
   to preparing
4. D.
   prepare

Answer 1

B
本题主要考查be busy这个结构后面接to do还是接doing。在英语中，大多数“be+形容词”的后面都是接不定式to do，但有少部分是接doing的，上述例题be busy doing就是其中一例。例如：
Our headmaster is busy talking with others.我们校长正忙着跟别人谈话。
She is busy telephoning her mother.她正忙着给妈妈打电话。