完形填空。
I can’t remember when I started collecting litter. But it was when I got tired of ________ litter nearby that I realized no one else was going to pick it up.
I live near a forest in Ohio, America. I can walk there ________ three minutes. I used to love going there to play with my dog. But one day there was________much litter there that I became very unhappy. I decided to clean up the forest, and I wanted to ________ happy when I went again. I made my first trip to clean the forest that afternoon. I took a big black rubbish bag with me. Ten minutes________  I started to pick up litter, my bag was full! There were cans, bottles, broken glass and newspapers in it.
From then on, I ________ to the forest four times a year to pick up litter. I often stay there for three hours. It makes me feel ________ to do something for the environment. After each trip, I look through all the litter that I’ve collected. If ________ of it is recyclable（可回收利用的）, I’ll keep it. I can’t understand why people drop litter. But I will keep on picking it up ________ they stop dropping it. I know I am only doing a small bit ________  the earth, but I still think it is important.

A．seeing B．throwing C．dropping D．cleaning

A．after B．for C．with D．in

A．such B．very C．so D．too

A．make B．feel C．look D．find

A．after B．later C．before D．of

A．had gone B．have gone C．go D．will go

A．tired B．sad C．interesting D．great

A．many B．few C．any D．much

A．until B．after C．as soon as D．when

A．helped B．to help C．help D．helping