Before you make a decision, you should _______ the advantages and disadvantages carefully.
Where do you think ________ we can buy that bestseller?
There is no doubt that eating organic food will make you healthier, ________?
It was today's activity ________ let me know the importance of teamwork.
—Why wasn't John hired for the job?—I don't know, but he ________.
She brought with her three friends, none of ______ I had ever met before.