下列关于商业汇票说法中，正确的有（）。

A.商业汇票的承兑人是付款人

B.商业汇票的承兑人一律为银行

C.商业汇票提示付款期限为自汇票到期日起10日

D.商业汇票提示付款期限为自汇票到期日起6个月

20. _______, English is one of the most important subjects.

A．It is known to all that

B．As is known to all that

C．As we know

D．As it is known to all