Christina wasn’t saying anything, but the professor smiled at her _______she had done something very clever. 
#31695
A
as if
B
now that
C
while
D
though
推荐题目
 It was several years ________ I realized ________ David had lied to me.
#30066
A
when; that
B
that; when
C
before; that
D
until; why
You may use the room as you like      you clean it up afterwards.
#31417
A
so far as
B
so long as
C
in case
D
even if