问题
实验题
在做氨的催化氧化实验时，铂丝不能接触氨水，原因是…（ ）
A．铂丝的温度高，接触氨水会使氨气大量逸出
B．红热铂丝会与氨水反应，使铂丝腐蚀
C．防止铂丝温度降低而不能起催化作用
D．防止爆炸
答案
答案：C
铂丝催化反应时，必须在一定温度下才能进行。较高效率催化氨的氧化，铂丝须处于较高温度下。
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在做氨的催化氧化实验时，铂丝不能接触氨水，原因是…（ ）
A．铂丝的温度高，接触氨水会使氨气大量逸出
B．红热铂丝会与氨水反应，使铂丝腐蚀
C．防止铂丝温度降低而不能起催化作用
D．防止爆炸
答案：C
铂丝催化反应时，必须在一定温度下才能进行。较高效率催化氨的氧化，铂丝须处于较高温度下。
| 完形填空。根据短文大意，从各题所给的选项中选择可以填入空白处的最佳选项。将其代号填入题前括号内。 | |||
| Jack is an English teacher at a college. He moved to New York City 1 all the members of his family. Jack is an excellent teacher, so we’ve all 2 him very much since he left. It was not long before Jack came back to North Carolina for a short 3 . The teachers and students held a small party for him. At the party, people walked around and 4 with each other. I certainly would not give up that good chance to learn English. So I tried to think of all kinds of topics to talk with Grace, another _____5____ teacher. Just before I was about to run out of my topics, suddenly I 6 Jack say to others loudly, “I dig New York!” I immediately asked Grace, “Is it really difficult to find a 7 in New York? Why does Jack haveto do 8 work since he is such a good teacher?” Grace didn’t seem to 9 what I said, “Why do you think that?” she asked. “Haven’t you heard him say that he is digging New York? Is he building an underground passage (地下通道)?” I asked. When she finally realized (明白) what I meant, Grace laughed to tears. She then asked us whether (是否) we 9 the meaning of “I dig New York.” All of 10 shook heads and said no. So Grace asked Jack to explain it to us. It turns out that “ I dig New York.” means “I love New York.” in American slang (俚语). Though few people say that now, we still hear it from time to time. | |||
| ( )1. A. after ( )2. A. missed ( )3. A. trip ( )4. A. talked ( )5. A. Chinese ( )6. A. heard ( )7. A. teacher ( )8. A. busy ( )9. A. knew ( )10. A. her | B. with B. loved B. holiday B. spoke B. English B. listened B. job B. free B. got B. them | C. of C. liked C. talk C. helped C. maths C. made C. work C. heavy C. thought C. you | D. in D. thought D. visit D. danced D. music D. told D. book D. easy D. heard D. us |