小船在宽为L的河中横渡,水流速度为V1,船在静水中的航速为V2,已知V1<V2,若小船的船头始终正对对岸,到达对岸所用的时间为t1,小船到达正对岸所用的时间为t2,小船渡河所需的最短时间为t3,小船渡河位移最小所需的时间为t4,则 下列选项正确的是 ( )
—Do you know _________ the new national park?
—Yes, I do. To protect wildlife and benefit the local people.
why did China set up
why China set up
when did China set up
when China set up
On our farm, the tea leaves ________ by hand when they are ready.
pick
picked
are picked
were picked
Jim _________ a lot about Chinese culture since he began to study in our school.
learns
learned
will learn
has learned
I ________ about my sister when my phone rang. It was her!
think
will think
was thinking
am thinking
Don’t lose heart. If you keep working hard, you _________ some day.
will succeed
succeed
succeeded
have succeeded