In order not to be disturbed ,I spent three days ________ in my study.  
#98167
A
locking
B
locked
C
to lock
D
lock
推荐题目
____ regular training in nursing,she could hardly cope with the work at first.
#95321
A
Not having received
B
Since receiving
C
Having not received
D
Not received
Jack became seriously ill after ________ in polluted air for many years.
#89778
A
breathed 
B
breath 
C
breathing 
D
to breathe