The pupil could add and subtract but hadn't learned to divide.
In shops you will have seen cash registers which basically can only add.
你谅必在商店里见过现金收入记录机,它基本上只能做加法运算.
The vast windows, by the standards of commercial jets, also add to a feeling of space.
大大的机窗是按照商用喷气式飞机的规格来设计的, 也能扩大空间感.
Having said all of the above, it's important to add that we shouldn't try too hard to be happy.
上面说了这么多,有必要补充说明的是,我们不应该过分追逐幸福。
The pupil could add and subtract but hadn't learned to divide.