let in: 讓…進入、放…進來
A braver step would be to let in foreign operators to boost competition.
更大膽的舉措便是讓外國同行進入中國市場以提升航空業的競爭水平。
China let in the foreign carmakers, but on condition that they worked with local partners.
中國則允許外國汽車制造商進入，但條件是他們必須與本國汽車制造商合伙經營。

work out: 解決、找到答案
I just have that confidence that things are going to work out fine.
我就是有信心，相信事情總是能解決得很好。
What is not easy to work out is exactly how many photons have arrived.
比較困難的問題是，精確的計算出到底有多少光子到達。

by now: 至此、到如今
By now the desk should be looking significantly tidier!
現在桌子看起來整潔多了。
By now I own some forty copies of the magazine.
到目前為止，我擁有大約40本《假日》雜志。