下列各项中可以构成设计变更的有( )。A．双方对工期要求的变化 B．施工条件和环境

Dear Mrs. Winthrop,

　　So my first week at college is over! No lectures this morning so I think I’d email you and let you know what things are going.

　　I’m glad to say that anything has worked out fine in the dorm. I remember asking for a room as far away from the lifts as possible and they find me a comfortable one second floor. There are two girls from my course here and I plan to make friend with them so we can help each other on the course work. Everyone else seems very nice and warmly here.

　　Well, I had better to stop now. I’m going to attend mine first lesson this afternoon, for I’ve got some preparation to make, Keep in touch.

　　Best,

Carol

2008届本科毕业生从事的行业大类排名

2008届从事第二产业的本科毕业生占其就业总数的比重约是（）。

A．53%

B．48%

C．43%

D．40%

信号领工员每月深入现场，检查和解决生产中问题的时间，不得少于月份工作计划的（）。

A、1/2

B、1/3

C、2/3

D、1/4

图示两个相啮合的齿轮，A、B分别为齿轮O₁、O₂上的啮合点，则AB两点间的加速度关系为( )。

一物体做直线运动的速度时间图象如图所示，第1、2s为第Ⅰ段，第3、4s为第Ⅱ段，第5s为第Ⅲ段，则下列说法中正确的是（）

A.第1s内的加速度大于第5s内的加速度

B.第1s内与第5s内的加速度方向相反

C.第Ⅰ段与第Ⅲ段平均速度相等

D.第Ⅰ段和第Ⅲ段的加速度与速度的方向都相同