《永遇乐·京口北固亭怀古》感叹东吴那个强盛的局面，孙权那个英雄、风流余韵，都经历了无数的风雨，一去不返了，只留下京口供后人欣赏凭吊而已的句子是：____，____。
Nowadays, more and more students choose to take a gap year. That is, they take a year ____ between the ending of high school and the beginning of university.
比较指标
①
②
③
④
酶Y活性/酶X活性
100%
50%
10%
150%
酶Y氨基酸数目/酶X氨基酸数目
1
小于1
大于1
