If the condor population has tripled since two decades ago, about how many are there now（）

单项选择题58（）

A. see you tomorrow
B. I have your name
C. check in
D. I have one
E. to take a look
F. you want
G. are you interested in
H. I have to put you in the waiting list

单项选择题Which of the following is the best title of this passage（）

A．Family.
B．American Families.
C．Family Types.
D．Four Family Types in Americ