They saw the bird flap its wings and ________ away.
A. fly
B. flied
C. flew
D. flying
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I insisted that the textbook ________ to be bought at once.
A. refers to
B. refer
C. referred
D. referring
________ , ice will be changed into water.
A. Heating
B. Heated
C. If heating
D. To be heated
The foreigner seemed ________ his way.
A. to be losing
B. to have missed
C. to have lost
D. missed
- What caused the party to be put off?- ________ the invitations.
A. Tom delayed sending
B. Tom’s delaying sending
C. Tom delaying to send
D. Tom delayed to send
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