3.Once the paper makers had shown people how to make paper，it came into widespread use all over the world.

一旦造纸者给人们展示了如何造纸，它就在全世界得到了广泛的应用。 once"一旦"，作连词，引导条件状语从句。 Once you get into a bad habit，you'll find it hard to get rid of it.

一旦你染上坏习惯，你会发现很难改掉。 4.Without her work，there would be very few mountain gorillas left today.

没有她的工作，今天，山地大猩猩将所剩无几。 without短语表示虚拟条件，引导含蓄虚拟语气结构。 Without you，I wouldn't have finished the job so quickly.

若没有你，我不会这么快就完成这项工作。 　　

　　 refer to谈到，涉及到；参考，查阅

　　(教材P46)Sometimes we use a different suffix，usually ­ess，when referring to a woman.

　　当指女性时，有时我们用不同的后缀，通常用­ess。

　　(1)refer...to...　 把......提交给......

　　refer to...as... 把......看作......

　　(2)reference n. 参考，查阅

　　make(a)reference to 谈到，参照

　　in/with reference to 关于，就......而论

　　①Even as a boy he referred to his father as Steve.

　　甚至当他还是小孩子时，他就叫父亲史蒂夫。

②You'd better write down the phone number of that restaurant for future reference