属于胸壁良性肿瘤的是（）。 A.一般较局限，呈圆形或椭圆形 B.均有包膜 C.局部肌

已知函数f（x）=x²-2x．

（Ⅰ）指出函数f（x）值域和单调减区间；

（Ⅱ）求函数f（x）在（0，0）点处的切线方程；

（Ⅲ）求f（x-1）＞0的解集．

下列运算正确的是[ ]

A．a³a²=a⁶

B．（﹣a²）³=﹣a⁶

C．（ab）³=ab³

D．a⁸÷a²=a⁴

能否实施有效的城市规划管理，必须熟悉行政效能知识和掌握提高行政效能方法。对城市规划管理来说，在行政效能中尤其要注重提高( )。

A．管理效益
B．管理效率
C．管理能力
D．管理质量

If you left your book on the table overnight, you would find the following morning that it was still exactly where you had left it, provided nobody had moved it. If a ball is made to roll on a very smooth surface, it will roll a long distance unless something stops it or changes its direction. This tendency of an object to remain at rest unless something moves it and to continue moving unless something stops it is known as the Law of Inertia.
The following examples show the truth of this law.
a. Put a table-cloth on a table and arrange a pile of books on it. Hold one edge of the table-cloth and pull it quickly. The table-cloth will come off, leaving the pile of books undisturbed.
b. Place a small piece of cardboard on an open jar and place a coin on it directly over its mouth. Use one finger to flick the piece of cardboard away. You will notice that the coin drops into the jar.
c. Sitting in a car which starts suddenly, you feel you are jerked backwards. In fact, you are not jerked backwards. Your lower half, which is in contact with the cushion, is forced to move forward with the car, and the upper part of your body, which remained at rest, is left behind.

A book put on the table overnight would ______ the following morning.

A. not be found again
B. not be touched again
C. stay exactly where it was left
D. be provided to someone else

按照纵向强力构件在传递载荷过程中所产生的应力数目，船体的纵向强力构件分为哪四类？