________ on ten years of observation and study, Professor Wang announced that everyone dreams every night，whether they realize it or not.
#88276
A
Basing
B
Based
C
Been based
D
Having based
推荐题目
___ by thick bamboo and high forest, the ancient city hadn’t been discovered until the 1990s.
#95741
A
Surrounding
B
Surround
C
Surrounded
D
Having surrounded
After describing the planned improvements, she went on _______ how much they would cost.
#98428
A
to explain
B
explaining
C
to be explaining
D
having explained
by the advances in technology, many farmers have set up farms on their land.
#94658
A
Being encouraged
B
Encouraging
C
having encouraged
D
Encouraged