I want to write a letter in English,but I don't know ___ about.A.how to write B.what to write

问题描述:

I want to write a letter in English,but I don't know ___ about.A.how to write B.what to write

a

B,因为后面有个about,没有的话才选A。

答案:B
what + 动词不定式,作know的宾语,what 作write about 的宾语,而how是副词,不能充当其宾语,所以正确答案是B.

B