By the time Billy was 6, he         in the sea.
#101498
A
had already swum
B
was already swimming
C
has already swum
D
already swam
推荐题目
Every means ______ tried but without any result.
#104352
A
have been
B
is to be
C
are to be
D
has been
If you _________ reading that book, take it back to the library.
#100473
A
have finished
B
will finish
C
finished
D
are finishing
--- May I visit you at 10 o’clock tomorrow morning?--- I’m afraid I ______ a document for my boss then. What about 12:00?
#100864
A
am preparing
B
will have prepared
C
will be preparing
D
have been preparing