1．The problem is difficult for a little girl to ________.
A．solve it B．work out it C．work it out D. work out
答案：D [因The problem充当句子的主语，在逻辑上是work out的宾语，故应选D。]
2．I can’t go home now.A lot of work ________ to be done.
A．stays B．is staying C. remains D．is remaining
答案：C [remain在此处为动词，其后接不定式，意为“仍然……”。一般不用于进行时中。]
