1. Why don't you put a better lock on the door, John?

`->` Mary suggested that John should put a better lock on the door

`->` Marry suggested a better lock should be put on the door by John

2. I haven't met her for 2 years

`->` It has been 2 years since I met her

`->` The last time I met her was 2 years ago 

3. Farmers can protect their land by planting some crops on the land

`->` If the farmers plant the same crops on the land, they can protect their land

4. We like traveling to Dalat. It is always cool and Beautiful there (where)

`->` We like traveling to Dalat where is always cool and beautiful 

5. Ben Thanh market is the symbol of HCM City, it has four gates

`->` Ben Thanh market, which has four gates, is the symbol of HCM City

😊