单选题 Mrs. White has a hard time because she has six children ______.
A. look after B. to be looked after C. to look after D. looking after

【正确答案】 C
【答案解析】题意为“她有六个孩子需要照顾”，此处是不定式做后置定语修饰children，并且不定式中的动词与children为动宾关系，因此应该用不定式的被动形式。