---We found a buyer for our house, but then the sale _____.
--- Why not promote it by posting an advertisement online?
A. fell through B. got through
C. cleared up D. looked up
It is almost five years since Jimmy taught high school students and he _____ as an interpreter in a foreign enterprise.
A. served B. had served
C. is serving D. would serve
Guangdong province rolled out new guidelines, _____ offensive nicknames and online violence as school bullying.
A. defining B. defined
C. to define D. having defined
---I don’t understand why Catherine stopped short _____ she ought to have continued.
---It’s obvious that she lacked self-confidence.
A. when B. while
C. if D. as
Never turn down a job because you think it’s too small. You don’t know _____ it can lead.
A. how B. where
C. whether D. what
A scientist’s attempt to produce the world’s first gene-edited babies _____ are immune to HIV has sparked controversy in academia and the public.
A. as B. who
C. whom D. whose
