We should think hard ________ human activity has caused greenhouse effect.
| A．it is how that | B．how it is that |
| C．that how is it | D．how is it that |
Out of the train_______, well-dressed and waving to the crowd.
| A．a tall man stepped |
| B．was stepping a tall man |
| C．did a tall man step |
| D．stepped a tall man |
— Do you know how Chinese acupuncture reduces pain?
— Well, well, _______．I’ve never read about that.
| A．I can’t tell you |
| B．you really have me there |
| C．there is some doubt |
| D．what a shame |
In many cities of China, if an ambulance is_______ in a traffic jam, police will respond to the emergency.
| A．held up | B．held back |
| C．held down | D．held out |
— I don’t remember having ever seen John since last week．Has he gone somewhere?
— Not really．He_______ his newly-bought apartment.
| A．has decorated | B．was decorating |
| C．decorated | D．has been decorating |
— Have you ever been to the Summer Palace?
— I can’t quite remember．_______, it might have been during my childhood.
| A．If any | B．If ever |
| C．If possible | D．If so |