It was two years ago______his sister became a doctor.
A. that
B. where
C. who
D. What
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Jack called the airline to ___________his flight to Beijing this morning.
A. improve
B. believe
C. insure
D. cancel
To work __________with the machine,you must read the instructions carefully.
A. firstly
B. naturally
C. efficiently
D. Generally
She told us briefly about how they succeeded in ________ the new product.
A. develop
B. to develop
C. developed
Developing
We had a(n) ________ with him about this problem last night.
A. explanation
B. impression
C. exhibition
Discussion