----- I am certain David has told you his business troubles. ----- ______, it is no secret that he owes a lot of money to the bank. 

There is no doubt that I'm trying to do what is best, but ________ I have got to consider the cost.

The 18 college students in Fudan University should           show their greatest respect to their hero — Zhang Ninghai instead of being cold and unfeeling.

Mr.Brown ___ goes to bed before midnight.

Process so far has been very good．______，we are sure that the project will be completed on time．