两个相互接触的静止物体间[ ]
A、一定存在弹力
B、可能没有弹力
C、一定有静摩擦力
D、当两物体间的压力大小一定时，静摩擦力也一定不变
答案：B
4岁小儿，有方颅，肋骨串珠，“0”形腿，精神与睡眠尚好，血清钙2.5mmol/L、血清磷1.61mmol/L，碱性磷酸酶10菩氏单位。该患儿可能是（）
A.佝偻病初期
B.佝偻病激期
C.佝偻病恢复期
D.佝偻病后遗症期
E.呆小病
—Where is Jack? I haven’t seen him for a long time.
—He ______ HK with his family. I think he is having a wonderful time there.
A．went to
B．was in
C．has gone to
D．has been to
