如此---以至于---（引导结果状语从句）

简单句：

--- enough ----to do---        not--- enough ---- to do---

足够---能够干---（形容词、副词放在enough前，名词放在enough 后）

---too---to do---

太---以至于不能干---

这道数学题是如此难以至于我做不出。

This maths problem is so difficult that I can’t work it out.

This maths problem is not easy enough( for me ) to work out.

This maths problem is too difficult (for me) to work out.

2. so that---

in order that---

为了，为的是---（引导目的状语从句）

简单句：

in order (not) to do---

so as (not) to do---

我出发早为了赶上早班车。

I start (=set out=set off) early so that I can catch the early bus.

 started   (注意：时态前后一致)  could

I start early in order that I can catch the early bus.

I start early in order to catch the early bus.

I start early so as to catch the early bus.