重点讲解：
1. thanks to 幸亏；归因于；
例句：Painful typhoid injections are a thing of the past, thanks to the introduction of an oral vaccine.
自从发明了口服疫苗后，令人痛苦的伤寒疫苗注射就成为了过去9%Bq3tzo&luMSTHXgAX)。
2. at first 最初；起初；开始时；
例句：I tried not to take any notice at first but then I was offended by it.
起初我尽量不予理会，但后来我被惹恼了1iw38b9;656)G。
3. clear out 清理，整理；
例句：I took the precaution of clearing out my desk before I left.
我临走时特地事先把办公桌清理了一下_[^hW8Mp~l&DCm。
4. take off (突然)离开，走开，走掉；
例句：I had better take off.
我最好告辞了rQhJ4jQfsOkx。