Engines are to machines ________ hearts are to animals.

His father got him a job in a bank but soon it became clear　　　he was not fit for that kind of work. 

(2013·高考江苏卷)In the global economy，a new drug for cancer，________ it is discovered，will create many economic possibilities around the world.

(2009·江苏，23)Because of the financial crisis，days are gone ________ local 5－star hotels charged 6,000 yuan for one night.

We thought there were 35 students in the dining hall, ______, in fact, there were 40.