如果把向东行进10米作为+10，那么向东行-5米，实际是[ ]
A．向东行了15米
B．向西行了15米
C．向东行了5米
D．向西行了5米
答案：D
—We ______ talk loudly when we see the sign "Be quiet" on the wall.
—Yes, you are right. We should be polite in public.[ ]
A. must
B. mustn't
C. need
D. needn't
Our teacher told Simon _____ forget _____ the door. [ ]
A. not, to close
B. not to, to close
C. not, closing
D. not to, closing
