Turn off the water while you ________ your teeth or washing your hands.
A. were brushing B. brush
C. are brushing D. brushed
It ________ about eight minutes for sunlight (阳光) to travel from the sun to the earth.
A. takes B. spends
C. costs D. pays
Talk to your teacher and you will get help ________ you have a problem.
A. unless B. if
C. until D. so
We have friends to help us fight against pollution, and trees are one of ________.
A. themselves B. they
C. their D. them
Now, people regard drinking tea ________ a culture more than a habit.
A. as B. by C. of D. with
Our mother earth gives us ________ we need in our daily life.
A. nobody B. nothing
C. everybody D. everything
