_____ on time， this medicine will be quite effective.
| A．Taking | B．Being taken | C．Taken | D．Having taken |
By 16:30, ______ was almost closing time, nearly all paitings has been sold.
| A．which |
| B．when |
| C．what |
| D．that |
After the flooding, people were suffering in that area, _______ urgently needed clean water, medicine and shelter to survive.
| A．which |
| B．who |
| C．where |
| D．what |
The air quality in this city,_______ is shown in the report, has improved over the past two months.
| A．that |
| B．it |
| C．as |
| D．what |
______ I explained on the phone, your request will be considered at the next meeting.
| A．When |
| B．After |
| C．As |
| D．Since |
The Beatles, ______ many of you are old enough to remember, came from Liverpool.
| A．what |
| B．that |
| C．how |
| D．as |