.---Putting on a happy face not only helps us make friends but also makes us feel better. --- _______.
—How far can you run without stopping? —________.I've never tried.
—Would you mind answering some questions on shopping habits? —________.
Whatever he does,once he sets up a goal,he will start pursuing it without ________.
As is well-known,the brain performs a very important ________,which controls the nerve system of the body.
—What do you think of the project put forward by the Blacks? —Considering its real ________,it will be well worth putting into practice,I suppose.