1. importance　 2. effect　 3. agricultural　 4. economy　 5. pollution　

1.ABBAA DBACB 11.BBCAA BAAAD 21.AAADC BCDDB 31.ADDAD DCABA

6.　　　 　　　　　　　　　, he didn t feel a bit tired.

=Though he worked very hard, he didn t feel a bit tired. (表示让步)

5.　　　 　　　　　　　　　　　　　　　　　　　　　　　　, Lucie helped him to get better.

=After she had brought her father back to England, Lucie helped him to get better. (表示时间)

4. The poor of the cities,　　 　　　　　　　　　　　　　　　　　　, took up their guns.

=As they had lived such a hard life, the poor of the cities took up their guns. (表示原因)

3.　　　 　　　　　　　　　　　　　　, Defarge found Dr. Manette making a shoe.

= When he entered the small room, Defarge found Dr. Manette making a shoe. (表示时间)

2.　　　 　　　　　　　　　　　　　　　, Charles returned to France.

= As he was a brave man, Charles returned to France.) (表示原因)

1. Charles left France; he preferred to give up his fortune.

= Charles left France, 　　　　　　　　　　give up his fortune. (表示伴随状态)

20. She a　　　　 　being invited.

19. Heavy rain p　　　　 　the possibility of continuing the game.