255. The college entrance examination is drawing near and all the students are ploughing through their studies. What does the underlined part means _____.
___________ I toured Zhang Jiajie, I was deeply impressed with its beautiful scenery.
Although she is only 17 years old, she _________ drugs for two years.
He risked __________ his job to see me off.
I was ashamed _________ lied to my mother.
Doctors are doing research to find out what happens physically when people _________ smoking.