The school has developed an online system________ students can choose their own teachers.
| A．which | B．when | C．that | D．where |
The car ______ at the present speed until it reaches the foot of the mountain at about ten o’clock tonight.
| A．would go | B．went | C．will be going | D．goes |
Though ______, many laws of nature exist.
| A．not having been discovered | B．having not been discovered |
| C．not having discovered | D．having not discovered |
_____, I couldn’t find a solution to the problem.
| A．Might I as try | B．As I might try | C．I might as try | D．Try as I might |
The servant did _____ she could ______ the revolutionary.
| A．what, help | B．that, to help | C．what, to help | D．all help |
If you ______ the medicine you ______ better now.
| A．took ; would feel | B．had taken; felt |
| C．had taken; would feel | D．took; would have felt |