六、短文改错
I took part in a geography research study group in last term. Our   71 ______
topic was environmental pollution and protection. We took a variety               72 ______
of pictures showed the present pollution conditions of our city. To           73 ______
our surprised, there are still a lot of people doing silly things to our         74 ________
surroundings. Some people throw the rubbish anywhere they like,           75 ________
some cars give off harmful gases, and waste water is poured in                76 ________
rivers by some factories. Worse still, people sometimes had to make               77 ________
their ways through dusty winds as a result of pollution. Through             78 ________
our research, we come to know what everybody must pay attention          79 ________
to our environment and some measures should be taken to protect.           80 ________