---Where are you, Tom? ---Here in the sitting room, to Professor Smith.A. to writeB. writi

---Where are you, Tom?
---Here in the sitting room, to Professor Smith.
A. to write
B. writing
C. is writing
D. to be writing

A. to write(答案→)B. writingC. is writingD. to be writing解析：考查非谓语动词。句中现在分词writing作伴随状语。句意：——汤姆，你再哪儿？——在起居室，给史密斯先生写信。

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