____several times，but unfortunately，the boy still couldn’t smooth away the problem on his own.
#98193
A
Having been explained
B
The problem having been explained
C
The problem had been explained
D
Although the problem had been explained
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Tom does speak Chinese well, but his reading and writing skills leave much _______.
#98212
A
to improve
B
to be improved
C
improving
D
improved
________ your dog with me should be a good choice. Trust me and I’ll look after it well.
#90198
A
When you left
B
Leaving
C
If you leave
D
Leave
He got up late and hurried to his office, ______ the breakfast untouched.
#93387
A
left
B
to leave
C
leaving
D
having left