Question

Rei

(6)はなぜmust ではなくneedになるんですか？

@ 次の文の(    う内から適当な語を選びなさい。
⑰) What (w辺 / ought / should ) 1 do in this sitaaton?
(2) she started at seven, she ( have / should / ougut ) to be ere by no
(3) e (can / must / need ) have been angry with her.
(⑳ You (ought / can / may ) have left your umbrela on tne sam.
(5) Something terrible ( can / must / need ) have happened.

(@) She ( do / must / need ) not have called a taxt.