----- Perhaps John’s not in.

-----_______. Look, the light’s on.

A．Yes, he can be at home.

B．No, he couldn’t go out.

C．Yes, he must be at home.

D．No, he needn’t go out.

承诺的有效要件包括( )。

A．承诺需由受要约人向要约人发出

B．承诺必须在合理期限内作出并到达要约人

C．承诺的内容与要约的内容须完全一致，不得作任何改动

D．承诺必须表明受要约人决定与要约人订立合同