( ) - sir ,i'm sorry for not having handed in my homework on time ,but i have been very busyall these days.- no excuse for it,but i ____ drop it this time.a might b can c should d mustsir回答的那句话意思不懂.顺便讲一下四个词作为

( ) - sir ,i'm sorry for not having handed in my homework on time ,but i have been very busyall these days.- no excuse for it,but i ____ drop it this time.a might b can c should d mustsir回答的那句话意思不懂.顺便讲一下四个词作为
( ) - sir ,i'm sorry for not having handed in my homework on time ,but i have been very busy
all these days.
- no excuse for it,but i ____ drop it this time.
a might b can c should d must
sir回答的那句话意思不懂.顺便讲一下四个词作为情态动词的特殊用法.

( ) - sir ,i'm sorry for not having handed in my homework on time ,but i have been very busyall these days.- no excuse for it,but i ____ drop it this time.a might b can c should d mustsir回答的那句话意思不懂.顺便讲一下四个词作为
drop it的意思是let it go 算了
I can 我可以
might 也许
should 应该
must 必须