贫富差距问题会造成社会的不安全，这应该靠谁来进行保障？（）
A.个人
B.企业
C.家庭
D.社会
参考答案：D
Police are searching for an escaped criminal who is reported to _____ since he broke away from the prison．
A．have been missing
B．have lost
C．be missing
D．get lost
作图题：画出信号灯及一般照明灯符号图。
