I left out the following sentences. Thank you very much, Writeacher.

Question

1) I think everybody would work at a passion but many times (mistake) this is often not possible.
2) If I worked, I would work at a job because I'll need (I need) to put aside money for me and my family.
3) I wouldn't like a boring job or one which wouldn't be motivating.
When I'll work, I will certainly work at a career.
4) If you (better someone) works at a career, then it is the prospects of promotion and the opportunities of development that motivate you.

Answer 1

1) I think everybody should work at something he/she is passionate about, but many times this is not possible.

2) If I worked, I would work at a job to put money aside for myself and my family.

3) OK

When I'll work, I will certainly work at a developing a career.

4) If someone works at a career, then it is the prospects of promotion and the opportunities of development that motivate him or her.

Answer 2

In 1 and 4, you can write these either way. Both are considered correct.

he/she ... him/her

he or she ... him or her