更多"The(poison)()gases from the cars ha"的相关试题:
[填空题]The (poison) () gases from the cars have polluted the air.
[填空题]The(poison)()gases from the cars have polluted the air.
[填空题]The (poison) ______ gases from the cars have polluted the air.
[单项选择]Cars have traditionally been wasteful beasts. Every time a drop of gas explodes inside a cylinder(气缸), the energy gets passed along from the piston(活塞) to the crankshaft(曲轴), flywheel(飞轮), gearbox, drivetrain, and axles(轮轴). By the time the wheels actually turn, four fifths of the original energy has disappeared. The electric car goes a long way toward reducing wasted energy by replacing the internal-combustion engine with batteries. Even so, electric cars destroy about 60 percent of the energy because mechanical parts are still used to deliver energy from the bakeries to the wheels. Lately, though, engineers have come up with a far more efficient way to accomplish the same task: by using magnets in the wheels.
Why do electric cars still waste much of the energy
A. Because they have replaced the internal-combustion engine with bakeries.
B. Because they still use mechanical paas to transfer energy to the wheels.
C. Because they use magnets in the wheels which add weight to the car.
D. Because batteries are not powerful enough to drive the cars.
[填空题]Compared to luxury ears, economy cars have higher operation costs.
[单项选择]
Since the energy crisis, these big cars have become a real liability. They cost too much to run()
A. lack of reliability
B. substitute
C. costly means of transport
D. disadvantage
[填空题]Pollutants from cars create a ______ which people in cars are most exposed to.
[填空题]Pollutants from cars cause ______ , which can damage buildings and pollute rivers.
[单项选择]Learnabout Noble Gases(惰性气体)
1 Have you ever ridden on a balloon Many tourist spots offer balloon rides inorder for people to see the beauty of a place from above. A balloon contains anoble gas called helium(氦). Formerly, balloons contained hydrogenbut hydrogen is very flammable and dangerous when uncontrolled. Therefore, peopleshifted to helium, which is safer. Helium is safe because it has the propertiesof the noble gases.
2 People once believed that noble gases couldn’t chemically react at all. Forthis reason, they were called inert gases(惰性气体). They werealso listed under Group 0 in theold periodic table because scientists believed that the gases have zero valence(价)electrons in their outer shell. This was later proven to be untrue when somenoble gas compounds were discovered.
3 Thegases are elements, which share similar properties. These properties includebeing monoatomic, colorless, odorless, being able to conduct electricity, andhaving low chemical reactivity. Noble gas