现代突发事件的特点包括（）
A.不确定性
B.高危害性
C.综合性
D.扩散性
E.多样性
参考答案：A, B, C, D, E
—We all had a lot of fun at the barbecue yesterday. Pity you weren’t there.
— I really should have gone with you, but I ________ on some remaining problems.
A．was working
B．would work
C．worked
D．had worked
为了健康，建议每日饮用葡萄酒的量是？（）
A.<50ml
B.50-100ml
C.200—250ml
D.300ml
