The pen my father sent me as my birthday gift very well.A. is writtenB. writesC. writingD.

问题补充：

The pen my father sent me as my birthday gift very well.

A. is written

B. writes

C. writing

D. has written

答案：

A. is written

(答案→)B. writes

C. writing

D. has written

解析：句中的主语the pen所具有的性质特点是“写起来很好”，在这种情况下，动词不用被动语态。