Mr. Wu___this math problem____him many times, but he still doesn’t understand it.
#38768
A
explains ; to
B
has explained ; for
C
has explained ; to
D
explained ; with
推荐题目
They’re late. The film _______ for half an hour.
#41730
A
Has begun
B
has been on
C
started
D
has started
Trees and flowers ________every year to make our country more beautiful.
#36894
A
is planted
B
was planted
C
are planted
D
were planted