Question

ああ

（20）の解答は4番ですが、それになる理由をしりたいです。

(b) In many schools in the U.S.A., you (
)a uniform.
heed
(18)
[D] 空所に入れるのに, 適切なものを選びなさい。
(19) You (
Ohave only to ②have to only to ③only to have ④to have only
)keep walking straieht. and vou will find Bill's house.
(20) Some investors are worried bv the news. but they ( ) be.
Dcouldn't 2hadn't ③mightn't @shouldn't
(青山学院大)