Strengthener
助力器
??? 情景例句
I have just begun to learn and my serve isn't very good.
我剛剛開始學習，發球不太好。
There's no such thing as a free lunch.
天下沒有白吃的午餐。
Of course, many pictures are not 'about' anything.
當然，有很多畫是什么“意思”也沒有的。