4.14

1. 轻轻一推门就开了。
The door yielded to a gentle push.
2. 我认识学生们的面孔，但不知道他们的名字。
I know students by face,not by name.
3. 说话大声点，教室里的学生才能听到你讲的内容。
Speak louderly,and every student in the classroom will be able to hear you
4.轻点儿走，否则你会弄出声响儿吵醒婴儿。
Walk slightly,or you will make a noise and wake the baby.
5. 从物理学的观点来看，不同的波长有多少种，颜色就有多少种。

From a physical standpoint,there are as many colors as there are different wave lengths.