We use the following linking words to introduce a reason or purpose:

to introduce a reason: because, because of, as , since

Please could you let me know by tonight because registration for the course closes tomorrow.

The supplies were late because of a transport.

As/Since I have just been made a project leader, it is important for me to attend a project leadership training course.

to introduce a purpose: to + infinitive, in order (not) to + infinitive, so as (not) to + infinitive, in order that, so (that)

Could you stay later this evening to help us prepare tomorrow's presentation?

I am interested in developing skills in order to deal with conflict.

We worked overtime so as not to miss the deadline.

It is vital to develop my skills in order that I can effectively motivate my team.

We worked overtime so that the project was finished on time.

Linking words for reason and purpose