According to the passage, which of the following is important in explaining a muscle movement？
A. The flow of blood to the muscles.
B. Classical conditioning.
C. Protein interaction.
D. The entry of unpleasant stimuli through the cell membrane.
A．soB．howeverC．butD．or
A. so
B. however
C. but
D. or
A．workB．houseworkC．dutyD．business
A. work
B. housework
C. duty
D. business
John's father thought most children went to school by taxi.
A. Right.
B. Wrong.
C. Doesn't Say.
微信支付 
支付宝支付