They use computers to keep the traffic _______ smoothly.
#5026
A
being run
B
run
C
to run
D
running
推荐题目
The collapse of the World Trade Centre has put US economy in a difficult ___________.
#4935
A
occasion
B
case
C
situation
D
background
— Why are you so popular with your students?— As a teacher, I seldom give my students so difficult a problem ____ they cannot work out.
#4683
A
as
B
that
C
if
D
which
Wouldn’t it be for you to pick me up at four o’clock and take me to the airport.
#4931
A
free
B
vacant
C
handy
D
convenient