-----My uncle bought my grandfather a new camera, but he doesn’t know_____. ----- You can ask him to read the instructions first.
When you are swimming, ________ your ears. You can use earplugs (耳塞) to stop water getting into your ears.
Turn off the water while you ________ your teeth or washing your hands.
It ________ about eight minutes for sunlight (阳光) to travel from the sun to the earth.
Talk to your teacher and you will get help ________ you have a problem.
We have friends to help us fight against pollution, and trees are one of ________.