Though ______, many laws of nature exist.
#97974
A
not having been discovered
B
having not been discovered
C
not having discovered  
D
having not discovered
推荐题目
________ to overcome the difficulty,he works day and night.
#95399
A
Determined
B
Determining
C
To determine
D
To be determined
The     look on his face showed that he was greatly     of being left alone in the house.
#96029
A
terrified;terrifying
B
terrified;terrified
C
terrifying; terrifying
D
terrifying; terrified
I do not have a job. I would find one but I _____ no time.
#98108
A
had
B
didn’t have
C
had had  
D
have