There are over 58, 000 rocky objects in _______ space, about 900 of which could fall down onto _______ earth.
| A．the; the | B．不填; the | C．the; 不填 | D．a; the |
Please do me a favor— _______ my friend Mr. Smith to Youth Theater at 7:30 tonight.
| A．to invite | B．inviting |
| C．invite | D．invited |
This is not my story, nor ______ the whole story. My story plays out differently.
| A．is there | B．there is | C．is it | D．it is |
_______ you may have, you should gather your courage to face the challenge.
| A．However a serious problem |
| B．What a serious problem |
| C．However serious a problem |
| D．What serious a problem |
It is uncertain ________ side effect the medicine will bring about, although about two thousand patients have taken it.
| A．that | B．what | C．how | D．whether |
A lot of language learning,________ has been discovered, is happening in the first year of life, so parents should talk much to their children during that period.
| A．as | B．it | C．which | D．this |