20.
(A) what to do it
(B) how to do it
(C) how to do
(D) what to do

答案：登入後查看
統計： A(1), B(25), C(9), D(25), E(0) #569595

whale66622（111已上岸～謝謝阿摩）

B1 · 2018/05/22

#2807727

It tells what to do.

=It tells how to do it.

what 有〔代名詞〕的功能，後面不需要再加上it，否則重複了。

how 〔副詞〕

參考資料：

https://tw.answers.yahoo.com/question/index?qid=20060319000013KK13523&guccounter=1

同場加映→ https://tw.blog.voicetube.com/archives/50756