Since the 1970s, approximately 800,000 legal and 300,000 illegal ...

[joblessjake]

Since the 1970s, approximately 800,000 legal and 300,000 illegal new immigrants
  __________ the United States.
 
  A) are entering B) have entered C) enter

Question 2

By the late 1990s, after years of unrestricted traffic, the large number of immigrants
  __________ a financial burden for these states.
 
  A) became B) had become C) has become

[lauravaras]

Answer to Question 1

B

Answer to Question 2

B

[joblessjake]

Great answer, keep it coming

[kilada]

Thanks for the timely response, appreciate it