A) Hot-melt adhesives
B) Loss-of solvent adhesives
C) Anaerobic adhesives
D) Two-part mix adhesives
Anaerobic adhesives set up into hard, strong adhesives when ______.
A.The two parts of resin and catalyst are mixed
B.Squeezed into thin joints which block the oxygen
C.The solvents evaporate or penetrate porous adherends
D.The heat source is removed
A、In politics, a reformer may have just as strong a love of power as a despot.
B、And is it not, perhaps, a drug which—like opium—has to be taken in continually stronger doses to produce the desired effect?
C、When the Arabs, who had been used to living sparingly on a few dates, acquired the riches of the Eastern Roman Empire…
D、What he thought was, “I must have a Navy as good as Grandmamma’s.”
According to the passage, you should thank others for their help, because ______.
A.they'll spend m6re time and energy to help you
B.they'll return the favor when needing help
C.they'll think what they've done is worthy
D.they'll make a strong alliance with you
Why can't you see light when you look at a black hole?
A.Because most black holes are so far away.
B.Because the gravity of a black hole is so strong that it sucks? the light inward.
C.Because as the star's gases burn, it stops giving off heat and light.
D.Because as a star cools, its outer layers pull in toward its center.
Even if you are a good high-jumper, you can jump only about seven feet off the ground. You cannot jump any higher because the earth pulls you hard. The pull of the earth is called gravity.
You can easily find out the pull of the earth. If you weigh yourself, you will know how much gravity is pulling you.
Since there is gravity, water runs down hill. When you throw a ball into the air, it falls back down. Because of gravity, you do not fall off the earth as it whirls(旋转) around.
Then, can we get away from the earth and go far out into space? Now you can do it, because spaceships have been invented. Then spaceship will go so fast that it can escape the earth’s gravity and carry you into space.
(1) In this passage, the word “gravity” means_______.
A.the pull of everything.
B.the force of attraction(吸引) among objects.
C.the force which attracts objects towards the centre of the earth
D.the force which attracts the earth towards the sun.
(2) When you slip you always fall to the ground because_______.
A.the earth always turns round.
B.the earth has gravity
C.the earth’s gravity is greater than your weight.
D.you are careless.
(3) Gravity is strong that_______.
A.it can throw a ball into the air.
B.it makes you jump only seven feet.
C.it can let you fly away from the earth.
D.it can keep everything on earth.
(4) Because of gravity,_______.
A.water flows everything.
B.we can go everywhere by ship.
C.water always flows downwards.
D.fish can live in water.
(5) We can get away from the earth by spaceship because_______.
A.the spaceship goes very fast.
B.the earth can’t pull the spaceship.
C.the spaceship has a strong force.
D.the spaceship can jump higher than other things.
The British teenager has______ .
A.set up a software company
B.saved Yahoo from its decline
C.become wealthy with his app
D.developed a new model of mobiles