There must be ________ with the computer. 

He was a(n) ___________singer until the age of 40, when he turned professional.

Mr. Wang, a(n)_______editor and writer, is going to attend the conference to be held in Beijing next week.

After days of fantastic space trip, the three astronauts walked out of the spaceship, _______.

From his _______look, I could see that he didn’t believe what I said.