15.Without any word , she just__________into the distance.
A. started
B. stared
C. saw
D. looked
查看答案
16.The__________of this machine is simple.
A. operating
B. replace
C. protein
D. operation
17.The gas explosion was really__________.
A. frightened
B. frightening
C. fright
D. fighting
18.Edison__________the electric bulbs over one hundred years ago.
A. found
B. discovered
C. thought
D. invented
19.Taste and__________are closely connected.
A. smell
B. legs
C. mouth
D. hearing