下列关于有机物的说法正确的是 A．乙烯与Br2发生加成反应生成CH3CHBr2

( )是以焊接铝管或铝箔为中层，内外层为聚乙烯材料，或内外层均为高密度交联聚乙烯材料，通过专用机械加工复合成一体的管材。

A．交联聚乙烯管

B．硬聚氯乙烯管

C．无规共聚聚丙烯管

D．铝塑复合管

用经纬仪或拉线和尺量检查混凝土设备基础的纵模轴线允许偏差为±20mm。

自然环境对人们的生产、生活影响较大。[     ]

I was a single parent of four small children, working at a low paid job. Money was always tight, but we had a (1) over our heads, food on the table, clothes on our backs, and if not a lot, always (2) . Not knowing we were poor, my kids just thought I was (3) . I’ve always been glad about that.

It was Christmas time, and although there wasn’t (4) for a lot of gifts, we planned to celebrate with a family party. But the big (5) for the kids was the fun of Christmas (6) .

They planned weeks ahead of time, asking (7) what they wanted for Christmas. Fortunately, I had saved MYM120 for (8) to share by all five of us.

The big (9) arrived. I gave each kid a twenty-dollar bill and (10) them to look for gifts of about four dollars each. Then everyone scattered. We had two hours to shop; then we would (11) back at the "Santa’s Workshop".

Driving home, everyone was in high Christmas spirits, (12) my younger daughter, Ginger, who was unusually (13) . She had only one small, flat bag with a few candies—fiftycent candies! I was so angry, but I didn’t say anything (14) we got home. I called her into my bedroom and closed the door, (15) to be angry again. This is what she told me.

"I was looking (16) thinking of what to buy, and I (17) to read the little cards on the ’Giving Trees’. One was for a little girl, four years old, and all she (18) for Christmas was a doll. So I took the card off the tree and (19) the doll for her. We have so much and she doesn’t have anything. "

I never felt so (20) as I did that day.

14（）

A.since 

B.after 

C.while 

D.until

热轧型钢的（）主要包括：切断、冷却、矫直、检查、捆扎等工序。

A、加热

B、精整

C、轧制

D、退火