---What have you learned from your experience in the USA?---Well, meeting people from another culture ______ be very difficult.
______, I love soft music more than popular music.
I _____ give you this book today, but I forgot.
His health had_____ while he was in prison.
We should never _____ ourselves with a little book knowledge only.
The substance can be added to gasoline to ______ the speed of automobiles.