There are two dogs in my family. One is white, black. A．anotherB．othersC．the otherD．oth——青夏教育精英家教网——

There are two dogs in my family. One is white,_____________ black.

—________ you open the window, please?
—Yes, I can.

— Tomorrow is Saturday, why don’t we play basketball in the gym?
—Good idea, ________ I have to see my grandparents.

—Peter, what’s your mother doing now?
—She____________in the kitchen.

We won’t go to the park if it ________ tomorrow.

They decided ______ for the children in Yunnan earthquake area.

A．do something

B．to do something

C．doing anything

D．done anything

I love my hometown and I _______ here for 15 years.

（本小题满分12分）
如图，四边形

是直角梯形，∠

所成的角为60°.

（Ⅰ）求证：平面

；
（Ⅱ）求二面角

（本小题12分）如图，四棱锥

是边长为2的正三角形，且与底面垂直，底面

的中点.
(1)求

所成角的大小；
(2)求证：

；
(3)求二面角

（（本小题满分12分）
如图，在四棱锥P—ABCD中，

底面ABCD，底面为直角梯形，

且AD=2，AB=BC=1，PA=

（Ⅰ）设M为PD的中点，求证：

平面PAB；
（Ⅱ）若二面角B—PC—D的大小为150°，求此四棱锥的体积.

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