We use a number of expressions to show that what is said follows logically from what was said before.

Keywords are:

*Therefore, as a result, so, then, consequently*

- She was
**therefore**unable to find a solution. **So**she had to quit her job.- I think;
**therefore**I am. - ‘We have missed the train.’ ‘
**Then**we are going to have to hire a taxi.’ - They grew up in Japan;
**hence**their interest in Zen Buddhism. - He sustained severe injuries and,
**consequently**, spent the rest of his life in a wheel chair.

**Therefore** is common in mathematical proofs.

**Hence and thus**

Hence and thus have the same basic meaning and are often interchangeable. However, there is a slight difference. Hence usually refers to the future. Thus usually refers to the past. It is often used to indicate a conclusion.

- Both sides played well, thus no winner was declared.
- The situation is getting more and more complicated. Hence we will have to proceed with caution. (NOT Thus we will have to proceed with caution.)

**So and then**

There is a difference between **then** and** so**. Then is used when one speaker replies to another. So can be used in both ways.

- ‘The last bus has gone.’ ‘So/ then we will have to walk.’ (Two speakers)
- ‘The last bus has gone, so we will have to walk. (NOT ‘The last bus has gone, then we will have to walk’) (Same speaker)