如图所示,在一只不计重力和厚度的塑料袋中装入大半袋水,用弹簧测力计钩住并将其慢慢浸入水中,直至塑料袋中的水面与容器中的水面相平.此过程中弹簧测力计的示数()
A:逐渐减小到零
B:先减小后增大
C:始终保持不变
D:逐渐增大
用镜头焦距为50cm的照相机拍摄人像时,人与照相机镜头的距离应该( )
阅读理解A
Millie:I usually ride my bike to schoo1.It takes me about twenty minutes.Sometimes,my father drives me to school in his car.
ff:My sister Mona and I like running to school.Running is good for us.Usually we leave home at half past seven.Then we get to school at seven fifty.
Alice:I don't like getting up early in the morning.So I have no time for breakfast at home.I usually have it on the school bus.I like my is ride because in the thirty minutes,I can eat my breakfast and walk with my friends.
Mike:My home is ten kilometers from my school.Every morning I
get up early.After breakfast l walk to the subway station.That
takes about ten minutes.Then I take the subway to school.It takes
twenty minutes.