`1.` It takes Nga 4 hours a day to practice English with her friends.
`2.` I wish you had taken the doctor's advice.
`3.` He suggested using fewer plastic bags.
`4.` Minh has collected stamps since 2000.
`5.` It's very important to keep the environment clean.
`6.` The last time we saw Mike was when we left the university.
`7.` Nam said they were going to celebrate a party at the weekend.
`8.` Because it rained heavily this morning, we couldn't go to school.
`9.` Mark isn't old enough to get married.
`10.` Unless you leave me alone, I will call the police.
`11.` We spent 3 hours opening the door.
`12.` You play tennis better than I do.
`13.` I wish I had more time to study.
`14.` Mary asked me if I had got any free time the following week.
`15.` Henry wished he hadn't bought the second-hand car.
@ `Ly`
