There is a mistake in each of these sentences. Underline the mistake and then correct it

There is a mistake in each of these sentences. Underline the mistake and then correct it
1. The ao dai is the traditional dress of Vietnamese women
2. the design and material are used for men were different from those used for women
3. They have added these patterns into the ao dai .
4. In the 18th century jean cloth was made completely by cotton .
5. In the 1990s the worldwide economical situation got worse .
6. wearing uniforms help students feel equal in many ways .
7. Rice are grown in tropical countries.