In China, people usually ________ firecrackers to celebrate the Spring Festival.
A. set outB. set upC. set aboutD. set off
The conflict had developed into a stage ________ the two countries were gathering big troops on the border.
A. whereB. whichC. thatD. when
—Why was Professor Smith unhappy recently?
—Because the theory he stuck to ________ wrong.
A. provesB. was provedC. provedD. proving
Today, the forests have almost gone. People must ________ down too many trees.
A. stop to cutB. stop from cutting
C. be stopped to cutD. be stopped from cutting
The growing speed of a plant is influenced by a number of factors, ________ are beyond our control.
A. most of themB. most of which
C. most of whatD. most of that
Anyone ________ has a dog as a pet will tell you ________ a dog means to a family.
A. who; whatB. who; whyC. which; whatD. which; why
