listen to the material carefully,although it is difficult and sometime you can't write down the correct answer.As long as you have tried,whatever you write down will be the harvest of yours.You should believe that only by accumulating little by little could you learn English welll.so come on.
At last firemen have put out a big forest fire in Califoria. Since then, they have been trying to find out how the fire began.(1)__________________________. Yesterday the firemen examined the ground carefully, but were not able to find any borken glass. They were also quite sure that a cigarette end did not start the fire. This morning ,however, a fireman accidentally discovered the cause.(2)__________________________. In this way ,he was able to solve the mystery. The explanation was simple but very unusual. A bird had snatched up the snake from the ground and then dropped it on to the wires. The snake then wound itself round the wires. When it did so,(3)_______________________.