证明可微的必要条件定理：设z=f(x，y)在点(x0，y0)处可微，则f’x(x0，

Any car accident is frightening, but an accident in which your vehicle is thrown into the water, with you trapped inside, is absolutely terrifying.   小题1:  However, most deaths result from panic, without a plan or understanding what is happening to the car in the water. By adopting a brace(支撑) position, acting decisively and getting out fast, you can save yourself from a sinking vehicle.

Brace yourself for impact (撞击力). As soon as you're aware that you're going off the road and into a body of water, adopt a brace position. The impact could set off the airbag system in your vehicle, so you should place both hands on the steering wheel in the "ten and two" position.

Undo your seatbelt.   小题2:  Unbuckle the children, starting with the oldest first. Forget the cell phone call. Your car isn't going to wait for you to make the call.

  小题3:  Leave the door alone at this stage and concentrate on the window. A car's electrical system should work for up to three minutes in water, so try the method of opening it electronically first. Many people don't think about the window as an escape option either because of panic or misinformation about doors and sinking.

Break the window. If you aren't able to open the window, or it only opens halfway, you'll need to break it with an object or your foot. It may feel counter-intuitive (有悖常理的) to let water into the car.   小题4:

Escape when the car has equalized. If it has reached the dramatic stage where the car cabin has been filled with water and it has become balanced, you must move quickly and effectively to ensure your survival.   小题5:  While there is still air in the car, take slow, deep breaths and focus on what you're doing.

A．Open the window as soon as you hit the water.

B．Surviving a sinking car is not as difficult as you think.

C．It takes 60 to 120 seconds for a car to fill up with water usually.

D．Such accidents are particularly dangerous to the risk of drowning.E.In conclusion, if you know what to do in the water, you will be safe.

F.This is the first thing to attend to, yet it often gets forgotten in the panic.

G.But the sooner the window is open, the sooner you can escape directly through it.

行为与后果的关系是[     ]

A、二者具有依赖性

B、二者具有相互促进性

C、二者具有一致性

D、二者具有排斥性

作乳剂型软膏剂的防腐剂是

A．油质性基质
B．水溶性基质
C．栓剂基质
D．乳化剂
E．气雾剂的抛射剂

托儿所

针对省国税、省地税的行业应用需求，今年我们新推出了移动税务的产品是（）

A.国税通

B.地税通

C.税务通

D.税法通