If ____ unsolved, the problem of food safety may lead to more serious results.
#94614
A
making
B
remained
C
left
D
taking
推荐题目
He was busy writing a story, only _____once in a while to smoke a cigarette.
#92270
A
to stop
B
stopping
C
to have stopped
D
having stopped
______ a leading role in a new film, John has a chance to become famous.
#92669
A
Offer
B
Offering
C
Offered
D
T o offer
–Did you get your pay? –Yes, I remember ______. But I forget the exact amount.
#89725
A
paying
B
to be paid
C
having paid
D
being paid
During the flood many students volunteered ________ through the weekend, giving out food and water for the victims.
#88784
A
working
B
to work
C
to have worked
D
having worked