She looks up now，catching me 27　　 at her, causing her to say to her mother." Mom, Dad’s looking at me 28　　 .”

　 The last few days，I touch her arm，her face一anything- 　29　　 that when my wife and I return home，she will not be with and there will be nothing to30　　 ．I have so much to say, but no31　　 with which to say it

　　 My32　　 changed from the day I drove this child home from the hospital. I saw myself33　　 that day, and it has led to a lot of places that I would never have found on my own .

　　 She says，“It'll be all right，Dad．I’ll be home from school 34　　 .”I tell her she will have a great year but I say little else．I am afraid somehow to speak and I only hold on to our good-bye hug a little longer, a little35　　 .

I gaze into her eyes and 36　　 to go. My wife’s eyes follow her as she leaves us.37　　 do not．Maybe if I don’t look，I can imagine that she really hasn’t38　　 ；I know that what she is embarking upon (开始)is exciting and wonderful．I remember what the world looked like to me39　　 everything was new.

　　 As I walk to the car with my wife at my side，my eyes are wet，my heart is sore，and I realize that my life is 40　　 forever．

21．A．sister’s 　　　　　　　 B．teacher's　 　　　　　 C．mother's　 　　　　　 D．roommate's

11． 一条长为的线段夹在互相垂直的两个平面、之间，AB与所成角为，与所成角为，且，，，、是垂足，求(1)的长；(2)与所成的角

10．在三棱台中，侧棱⊥底面，且，．

(1)求证：，，．

(2)求异面直线和的距离．

9．已知不共面的三条直线、、相交于点，，，，，求

8．两条异面直线、间的距离是1cm，它们所成的角为60⁰，、上各有一点A、B，距公垂线的垂足都是10cm，则A、B两点间的距离为____________________．

7．在棱长为的正四面体中，相对两条棱间的距离为________________．

6．在正三棱柱中，若，则与所成的角的大小　　 ．　

5．已知异面直线a与b所成的角为50⁰，P为空间一点，则过点P与a、b所成的角都是30⁰的直线有且仅有(　　　 )

1条　　　　 2条　　　　　 3条　　　　　　 4条

4．已知直线a，如果直线b同时满足条件：①a、b异面②a、b所成的角为定值③a、b

间的距离为定值，则这样的直线b有(　　　　 )

1条　　　　 2条　　　　　 4条　　 　　　　无数条

3．AB、CD在平面α内，AB//CD，且AB与CD相距28厘米，EF在平面α外，EF//AB，且EF与AB相距17厘米，EF与平面α相距15厘米，则EF与CD的距离为(　　 )

25厘米　　　 39厘米　　　 25或39厘米　　 15厘米