一 1.harm 2.exist 3.puzzled 4.oxygen 5.atmosphere 6．fundamental7.multiplies
8.system9.mass10.Violent
二
Exist on C
Exist on, exist in ,there exist, come into existence
没有能够穿越空间的能力,我们就没有可能拯救自己。

Puzzle A, puzzling，puzzled
C c
Nothing can prevent us from fighting for freedom.
C C,C
Can we in time to catch the train at six o 'clock?
D AD C
∙ahead of time提前；提早from time to time不时，有时
∙in no time立刻，很快
∙in one's spare time 在某人的业余时间kill time消磨时间
take one's time慢慢来，别着急
∙at a time一次；每次；在某时
∙at one time曾经，一度；同时
∙at no time决不，从不at times有时；偶尔
∙for the time being暂时
∙behind the times过时，落伍，落在时代后面
In the west, people often make it a rule to buy Christmas gifts to relatives and friends.
Be harmful to, harm, 这件案子可能会严重损害我们的生意。

Be harmful to/ do harm to 做某事是无害的
BA CC
Lied, lay, laid
Lay aside 把。

放在一边；存储；积蓄
Lay off （暂时）解雇
Lay the table 摆桌子。