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unit5-1
I have to study English.
have to (has to)→~する必要がある
〈主語+have to (has to) + 動詞の原形〉
↓
↓
| have to
↓
study.
O→He has to study math.
→He has to studies math.
否定文→〈主語 + don't have to (has to) +動詞の原形〉
I don't
have to
unit5-2
I must play basketball.
play
baseball.
must→ ~しなければならない
O→He must study math.
He must studies math.
〈主語+must+動詞の原形〉
↓
↓
↓
must play
English.
否定文 〈主語+ must+not+動詞の原形〉
unit5-3
must not play
soccer.
I should help my mother.
should→~したほうがよい
<主語+ should+動詞の原形〉
↓
↓
I should help
my mother.
否定文 〈主語 + should + not+動詞の原形〉
I should not help
my mother.
O She should study math.
X-She should studies math.