26.—Flight MU257 _______________ . I must be off now.
—Have a nice trip.
| A．is being announced | B．has announced |
| C．was announcing | D．had been announced |
The plant is dead. I ____ it more water.
| A．will give | B．would have given |
| C．must give | D．should have given |
I didn’t go to the party, but I do wish I ____there.
| A．was | B．were | C．had been | D．went |
Although she is only 17 years old, she _________ drugs for two years.
| A．Addicts | B．has addicted to |
| C．has addicted | D．has been addicted to |
根据所给汉语，写出单词的正确形式It is said that the first ___________(定居者) of this country are prisoners.
This is the ________(标准) textbook on the subject.
He gave a ________(生动的) account of his life as a fighter pilot.
The _______(焦点) of the news is earthquake happening in Sichuan.
If the fire-alarm goes, ________ (全体员工) should assemble outside the building.
It is easier to float in the ocean than it is to float in a swimming pool. Do you know why?
Ocean water is full of salt— and salt water can hold up more weigh than fresh water. See for yourself!
You Will Need:
● 3 cups of warm water
● Measuring cup (量杯)
● Wide-mouthed jar
● Salt
● Spoon
● Raw (生的)potato
You Will Do:
1. Pour 1.5 cups of warm water into the jar.
2. Add 1/3 cup of salt.
3. Stir(搅拌) until the salt is completely dissolved.
4. Add another 1.5 cups of water. Pour it slowly over the back of the spoon into the jar so that the two liquid will not mix together.
5. Gently place the potato into the jar. Do not drop it.
What Will Happen:
The potato will sink— but only halfway!
Why?
Salt water is heavier than fresh water, so it will stay on the bottom. The fresh water will remain on top.
The potato is heavier than the fresh water, but it is lighter than the salt water. That is why the potato will sink halfway down.In the experiment, what should you do right after you pour the water over the spoon?
| A．Add the salt to the water. | B．Stir the salt into the water. |
| C．Place the potato in the jar. | D．Pour warm water into thejar. |
In Step 4 of the experiment, why do you pour the water over the spoon “slowly”?
| A．It is easier to see what you are doing. |
| B．It pushes the fresh water to the bottom. |
| C．It will keep the water from coming out. |
| D．It will keep the liquids from mixing together. |
In which step of the experiment do you add the salt?
| A．Step 1 | B．Step 2 | C．Step 3 | D．Step 4 |
What does the underlined word “gently” mean?
| A．Carefully | B．Quickly | C．Secretly | D．Silently |