Coal was formed out of dead forests through a long _____ of chemical changes.
#6229
A
stage
B
access
C
order
D
process
推荐题目
 In this research, two are _____, and the others are _____.
#6655
A
Swisses, Germans
B
Swiss, Germen
C
Swisses, Germen
D
Swiss, Germans
This dictionary is _____ to my reading, but that one is __________.
#6647
A
great help; helpless
B
a great help; of no use
C
important; of few importance
D
very helpful; of no any use