A. 10 percent to 25 percent for the proportion of workers who use drugs occasionally on the job
B. determine exactly when simple drug use becomes abuse
C. the 1920s until the 1960s
D. the 1960s until the 1970s
E. signals passing through the nervous system Drugs that speed up ______.

A．to clarify the British government’s stand on landmines
B．to establish her image as a friend of landmine victims
C．to investigate the sufferings of landmine victims there
D．to voice her support for a total ban of landmines

A．vague
B．transparent
C．alien
D．significant