.-Do you like to buy the product an advertisement______on TV?-Not really. I think it's better to look before we leap.
Do you think exercise can keep us ________?
The teacher asked us ________ in our reports before class.
Tom was the first ________ he was wrong.
—Send me an email when you are free, will you? —________.
Many students are ________ chatting online, which wastes them plenty of time.