呆小症是由于()
A.幼年生长激素分泌不足
B.幼年甲状腺素分泌不足
C.幼年生长激素分泌过多
D.成年生长激素分泌过多
E.成年甲状腺素分泌不足
参考答案:B
Japan has been trying to bring its nuclear crisis under ________ control, but ________ spread of radiation has raised concerns about the safety of the nuclear energy.
A.a; the
B.the; /
C./; the
D.a; /
现有一瓶某品牌的饮用纯净水.
(1)用手握住水瓶在空中静止不动,此时水瓶受到的重力和手对瓶的 是平衡力.
(2)瓶中水的体积是550mL,则水的质量是 kg.
(3)瓶中水喝光后,从瓶口向外吸气,瓶子变瘪,是由于瓶子受到 的作用.