Speaker A: I'm going to the park with some friends for a barbecue on Sunday. Would you like to join usSpeaker B: ______

A．Why not on Saturday You see, I have an important appointment on Sunday.

B．Thanks, but unfortunately I have to take my sister to the airport on Sunday.

C．That's a wonderful idea. Barbecue is one of my favorites.

D．What preparation do you expect me to do for the barbecue

承压壳体中工作应力的大小（）

A、与容器壁厚和直径D成正比，与压力p成反比

B、与压力p和容器壁厚成正比，与容器直径D成反比

C、与压力p成正比，与容器壁厚和容器直径D成反比

D、与压力p和容器直径D成正比，与容器壁厚成反比