[单项选择]Cotton farmers in Central America began to use pesticides
A. because of an intensive government advertising campaign.
B. in response to the appearance of new varieties of pest.
C. as a result of changes in the seasons and the climate.
D. to ensure more cotton was harvested from each crop.

[单项选择]By the mid-1960s, cotton farmers in Central America found that pesticides
A. were wiping out 50% of the pests plaguing the crops.
B. were destroying 50% of the crops they were meant to protect.
C. were causing a 50% increase in the number of new pests reported.
D. were costing 50% of the total amount they spent on their crops.

[单项选择]

The Voice of America began during the World War II when Germany was broadcasting a radio program to get international (21) . American officials believed they should (22) the German broadcast with words that they thought were the facts of world (23) . The first VOA news report began with these words in (24) : "The (25) may be good or bad, but we shall tell you the truth." Within a week, other VOA (26) were broadcasting in Italian, French and English.
After the World war II (27) in 1945, some Americans felt VOA’s (28) had to be changed, (29) the Soviet Union (苏联)became the enemy of America. They wanted to reach Soviet listeners. Then VOA began broadcasting in Russian.
In the early years VOA began (30) something new to its broadcast that was (31) "Music USA" , Another new idea came (32) in 1959. VOA knew that many listeners did not know (33) English to
A. American
B. British
C. standard
D. enough