一个球竖直向上抛出,当它到达最高上时具有重力势能是20J。若空气阻力不计,当它回落抛出点时的动能是____________ J,机械能是____________ J。
20;20
They had bought ______ furniture before they moved into the new apartment.
A. many
B. few
C. lot of
D. some pieces of
在《马关条约》中,最能体现外国资本主义对中国侵略进入新阶段的是[ ]
A.割让辽东半岛、台湾、澎湖列岛结日本
B.赔款白银二亿两
C.增开通商口岸
D.允许日本在中国开设工厂