制成品如门窗框，门窗扇要堆放在成品库，分层垫木上堆，垫木要上下错开.
参考答案：错
—My mother is ill. — .
A．I think so.
B．That’s OK.
C．Really? Thank you
D．I am sorry to hear that.
事故调查期限是怎样规定的？
