下列关于体育锻炼对运动系统影响的说法，不正确的是（）。

A.可减少交感神经张力

B.使骨骼增粗、骨骼腔增大

C.可降低迷走神经兴奋性

D.促进肌纤维增长变粗

E.使身体素质明显改善

Many Children ________ the Internet , and _____had a bad effect on their studies.

A．are addicted to; it

B．get engaged in; which

C．are related to; what

D．are addicted to; which