Exactly______ the potato was introduced into Europe is uncertain, but it was probably around 1565.
#30010
A
whether
B
why
C
when
D
how
推荐题目
______ you come across some new words, don’t refer to your dictionary at once but guess their meanings according to the context.
#30708
A
Every time
B
The first time
C
Now that
D
If only
The two military exercises were similar __________ they were both intended to give a threat to a certain country.
#31922
A
to what
B
for which
C
in that
D
except that
----What a beautiful picture! ----It’s years ______ I painted a picture as beautiful as this one.
#33288
A
that
B
since
C
when
D
before
Some people waste food，________other people haven’t got enough to eat.
#31933
A
when
B
until
C
since
D
while