皮肤的功能是（ ）
A．保护和调节体温
B．分泌和排泄
C．感受外界刺激
D．以上三项都是
答案：D
.---It’s a fine day. Why don’t you go camping with us?
----________. Let’s go.
A．It’s difficult.
B．No, thanks.
C．Sounds fun.
D．Sure, you can
He worked late ______ eleven o’clock yesterday.
A．after
B．until
C．since
D．at
