The research lacks evidence, and therefore, its conclusions are doubtful.

What do you think of the film So Young directed by Zhao Wei—Wonderful. I think it’s than the other films about youth in recent years.

To be honest, if it were not for the fact that you ____ my close friend, I would not take such painsto serve you.

_____ the population of China? — About 13 billion

________ your son is well again, you no longer have anything to worry about[ ]