It was never clear _____ the man hadn't reported the accident sooner．
| A．that | B．what | C．when | D．why |
—Are you free after school?
—Sorry: I’ve planned to treat a friend of mine to dinner for his help.
| A．in terms | B．in honor | C．in turn | D．in return |
—Alice, you look puzzled. Have you understood it?
—Yes, I another problem just now.
| A．have thought of | B．am thinking of |
| C．had thought of | D．was thinking of |
Whether ways will be found to stop pollution or not is just worries the public.
| A．why | B．which | C．that | D．what |
Travelersthat they should bring their ID cards with them.
| A．have reminded | B．are reminded |
| C．were reminding | D．had been reminded |
Shanghai has hosted2010 world Expo. The world Expo has long history but it has never been held in Asia.
| A．——；a | B．the ; a | C．the ; the | D．/ ; / |