施工企业在与施工机具供应商签订采购合同时应包括（）。
A.标的
B.租金及支付方式
C.交货期限及方式
D.违约责任
参考答案：A, C, D
—Did you attend the opening ceremony of The Voice of China last week?
—Sorry! We ________ it, but we had a terrible traffic accident on our way.
A．must have attended
B．must attend
C．could have attended
D．could attend
大气中的乱流也能产生垂直运动，可以形成（）
A.积雨云.雾或毛毛雨
B.层云.雷阵雨.阵性大风
C.A.B都对
D.A.B都错
