---_______do you send e-mails to your pen friend? ------Once a month.
#56239
A
How long
B
How far
C
How much
D
How often
推荐题目
it rained heavily this morning, nobody in our class missed the lesson.
#56424
A
Even though
B
Until
C
Ever since
D
Because
The rivers will become dirtier and dirtier _______ we take action to protect them.
#55533
A
since
B
if
C
until
D
Unless
A tourist will easily lose his way in Beijing ______ he has a map or a guide.
#58451
A
if
B
because
C
unless
D
when