17.Cold is a__________disease.
A. sharp
B. cycle
C. anesthetic
D. widespread
18.What__________you from coming to our party last night?
A. presented
B. afforded
C. prevented
D. observed
19.My sister in Beijing is very busy and__________writes to me.
A. often
B. frequently
C. once
D. seldom
20.This company__________children’s books.
A. encourages
B. researches
C. searches
D. publishes