—You seem to have known Dr. Ken for a long time.—That’s true. ________ he joined our club years ago.
#34031
A
Since
B
Until
C
When
D
If
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He waited ________ the volcano became quiet and he was able to return two days later.
#80251
A
when
B
before
C
as
D
until
______ the Internet is of great help, I don’t think it’s a good idea to spend too much time on it.
#32459
A
If
B
As
C
Because
D
While