在剪板机上安置的防护栅栏不能让操作者看不到( )的部位。
A.裁切
B.防护
C.剪切
D.废料
参考答案:A
When I was 19,I had got a job in my local bookstore. Living in the large city,I usually saw many strange customers(顾客),most of 1 were teenagers. They didn’t come often;I forgot all the customers 2 two. One night a 15-year-old girl came in looking for a book with a boy. They seemed to find what they wanted to buy. But 3 they came to the counter(柜台),the girl found she was a dollar or two short to buy the book,and she took
4 all her money to prove it. She looked so disappointed. Just then I remembered my discount card and 5 was still active,so I told the girl 6 to worry. I put in my code(密码),being happy that I could help them with this card. With the book in her hand she gave me 7 thankful smile,and then she and the boy got out of the store happily,leaving me feeling content,too. 8 fact, sometimes a little thing can also make one’s world beautiful.
如果用3H、15N、32P、35S标记噬菌体后,让其侵染细菌,在产生的子代噬菌体的组成结构成分中,能够找到的放射性元素()
A.外壳中可找到15N和35S、3H
B.DNA中可找到3H、15N、32P
C.外壳中可找到15N和35S
D.DNA中可找到15N、32P、35S