---Why is the classroom so dirty? --- Sorry, sir. It ______ yesterday. We forgot to do it. 
#44831
A
doesn’t clean
B
didn’t clean
C
isn’t cleaned
D
wasn’t cleaned
推荐题目
—Our school _________ in 1876. —Wow, it has a very long history.
#44656
A
built
B
was built
C
is built
D
has built
It is true that knowledge_____ rather than being taught. 
#44980
A
learns
B
learned
C
is learned
D
was learned
The Trojan War ______ by Helen and her beauty.
#44539
A
causes
B
is caused
C
caused
D
was caused
Our classroom   _______   by us every day!
#44538
A
is cleaning
B
has cleaned
C
must clean
D
is cleaned