a big headache令人头痛的事情
a fraction of 一部分
a matter of concern 焦点
a series of 一系列,一连串
above all 首先,尤其是
absent from不在,缺席
abundant in富于
account for 解释
in brief 简言之
no doubt 毫无疑问
in conclusion 总之，最后
undoubtedly 无疑
in short 简而言之
truly 的确
accuse sb. of sth.控告
agree with同意
ahead of time / schedule提前
ahead of 在...之前(ahead of time 提前
alien to与...相反
all at once 突然,同时
all but 基本上;除了...都
all in all 总之
all of a sudden 突然
certainly 当然地;无疑地
obviously 显然
eventually 最后
surely 无疑
finally 最后
to conclude 总而言之
in a word 总之
