--Who's knocking at the door?--I'm not sure Maybe___is my good friend Jack.A.he B.it C.she D.him

--Who's knocking at the door?--I'm not sure Maybe___is my good friend Jack.A.he B.it C.she D.him
--Who's knocking at the door?
--I'm not sure Maybe___is my good friend Jack.
A.he B.it C.she D.him

--Who's knocking at the door?--I'm not sure Maybe___is my good friend Jack.A.he B.it C.she D.him
--Who's knocking at the door?
--I'm not sure Maybe_it_is my good friend Jack.
B.it

b
因为你不知道外面的人的性别
这种情况就用it

b
不定代词用it

选B项