1/. 

The gender equality should be balanced by Asian countries 

2/.

Many seriousn road accidents will be caused by Dangerous driving 

3/. Applicants must return this form by 21st March.

This form must be returned by 21st March by applicant

4/. We will not accept his apology.

His apology  wont accepted

5/. I have never done a more difficult exercise than this before.

This is the most difficult exercise 

6/. This is the worst tennis player in this club I have ever played with.

I have never played with the worse tennis player in this club than this before 

1.Asian countries should balance the gender equality.

=> The gender equality should be balanced by Asian countries.

2. Dangerous driving will cause many serious road accidents.
=> Many serious road accidents will be caused by dangerous driving.

3. Applicants must return this form by 21st March.

=> This form must be returned by 21st March by applicants.

4. We will not accept his apology.

=> His apology won't be accepted.

5. I have never done a more difficult exercise than this before. 

=> This is the most difficult exercise I have (ever) done.

6. This is the worst tennis player in this club I have ever played with.

=> I have never played with a worse tennis player than this in this club before.

#NOCOPY  - best answer please ~