重点讲解：
1. concentrate on 全神贯注；集中（心思）；
It was up to him to concentrate on his studies and make something of himself.
是否能专心学习并取得一定成就要靠他自己MKKt|!-,X)tf7^L(U,Js。
2. for one's sake 看在…份上；为了帮助(某人)；
For safety's sake, never stand directly behind a horse.
为安全起见，千万别站在马的正后方+Fo@JpQnbL[Wc。
3. tally up 计算；合计；清点；
Bookkeepers haven't yet tallied up the total cost.
会计还没有计算出总成本S+eRR42&a*y.。
4. take sth. for granted 认为…是理所当然的；
We are having to re-educate the public very quickly about something they have always taken for granted.
我们现在不得不尽快对公众进行再教育，因为他们一直都认为这是理所当然的wI[ZCv4k=t[iEC0。