凡是在矿井开拓、采掘过程中,渗入、滴入、淋入、流入、涌入和溃入井巷或采煤工作面的任何水源水,统称()。
A、地表水
B、矿井水
C、老空水
D、地下水
参考答案:B
Teeth are important. Strong, healthy teeth help you chew all kinds of foods that help you grow. They help you speak clearly. And yes, they help you look your best. Here are some tips for you to take care of your teeth.
小题1:How many times at least should we brush our teeth a day?
A.1.
B.2.
C.3.
D.4.小题2:What is the major cause of tooth decay?
A.Not brushing teeth.
B.Not changing toothbrushes.
C.Eating sugar.
D.Not flossing teeth.小题3:How often should we change our toothbrushes?
A.Never.
B.Three times a month.
C.Every three months.
D.Every month.小题4:The bristles of the toothbrush must be_______.
A.hard
B.soft.
C.expensive.
D.not mentioned.小题5:Which is the right way to take care of your teeth?
A.Only brush front teeth.
B.Don’t brush teeth before sleeping.
C.Spend at most three minutes brushing teeth each time.
D.Eat lots of fruit and vegetables and drink water instead of soda.
There is no such __ person in the world.
A.a
B.an
C./
D.the