| A. that have died B. that has grown up C. make their city greener D. ask for help E. celebrates |
In San Francisco, there is a special group of volunteers. They call themselves Friends of the Urban (城市的) Forest (FUF). These volunteers want to . Every year, the FUF plants nearly 1,000 trees.
The FUF welcomes new volunteers all year round and in all parts of its work. On Weekend Planting Days, FUF volunteers work with common citizens (市民) to plant trees. The planting usually runs from 9 a.m. to 1 p.m. After the work is done, everyone over a community lunch.
On Thursday Planting Days, the FUF plants "replacement (替换) trees". As their name suggests, these trees replace trees . Planting Leaders are very experienced volunteers. They are able to help other volunteers at planting events. Planting Leaders usually wear a special FUF T-shirt. Some new volunteers know little about "replacement trees". They can easily find Planting Leaders and .
