1. I suggest using gas instead of burning coal
2.How about playing badminton?
3. Shall we buy energy-saving bulbs?
4.Why don't we use electricity economically?
5.I suggest you should ask her yourself
6. I suggest our classroom should be decorated again
7.I suggest a charity event should be organized to raise money
8.What about using that helmet to protect our heads 
9.I suggest a cultural festival should be organized to celebrate Lunar New Year
10. What about collecting unused clothes for the victims
11. The local authorities suggested garbage should be taken to recycling centers
12.Andrew suggested going to English speaking club
13.They suggested that an advertisement should be put in this local newspaper
14.Ba suggested Nam should repair the electric fan
15.Tom suggested not telling anyone until we are certain that the report is true