Helen _______her keys in the office so she had to wait until her husband ___home.

A．has left; comes

B．left, had come

C．had left; came

D．had left; would come

学校社会工作还可能以单亲家庭的孩子为对象。一般单亲家庭的分类有（）

A.收养孩子的家庭

B.离婚单亲家庭

C.分居单亲家庭

D.未婚单亲家庭

E.丧偶单亲家庭