若-1，a，b，c，-4成等比数列，则a·b·c的值为（ ）。

阅读理解。

     It's December thirty-first, New Year's Eve.Bob and Sally Simpson are celebrating the holiday with

their children, Lucy and Tom. the Simpsons are a very happy family this New Year's Eve. Next year is

going to be a very good year for the entire family.

     Next year, Bob and Sally are going to take a long vacation. They're going to visit  Sally's cousin in

California. Lucy is going to finish high school. She's going to move to Boston and begin college. Tom is

going to get his driver's license. He's going to save a lot of money and buy a used car.

     As you can see, the Simpsons are really looking forward to the next year. It's going to be a happy year

for the next year.

根据短文内容，判断正（T）误（F）。

( )1. It's New Year's Day.

(     )2. There are four persons in the family.

( )3. Lucy is going to college.

( )4. Tom's going to save a lot of money to buy a new car.

(     )5. Tom has his driver's license.

2008年北京奥运会的“祥云”火炬所用燃料的主要成分是丙烷，下列有关丙烷的叙述中不正确的是

A．分子中碳原子不在一条直线上

B．光照下能够发生取代反应

C．比丁烷沸点更高

D．丙烷没有同分异构体

如图所示，先后两次将同一个矩形线圈由匀强磁场中拉出，两次拉动的速度相同．第一次线圈长边与磁场边界平行，将线圈全部拉出磁场区，拉力做功W₁、通过导线截面的电荷量为q₁，第二次线圈短边与磁场边界平行，将线圈全部拉出磁场区域，拉力做功为W₂、通过导线截面的电荷量为q₂，则（　　）

A．W₁＞W₂，q₁=q₂

B．W₁=W₂，q₁＞q₂

C．W₁＜W₂，q₁＜q₂

D．W₁＞W₂，q₁＞q

冰川是由于雪长期重压而形成的冰雪混合体，它沿地面向低处慢慢移动，当到达海边时发生折断、崩塌，落入海洋形成冰山．冰山落入海洋后处于______状态（选填“漂浮”、“悬浮”或“沉入海底”）．若某一冰山的体积为V，位于海面下的体积为V₁，则V₁：V=______．（ρ冰=O.9×10³kg/m³．ρ海水=1.03×10³kg/m³）

220kV电压等级等电位作业人员对相邻导线的距离应不小于（）m。

A．2.4

B．2.5

C．2.6