The system is based _______ a network of metal pipes.

A. in
B. on
C. under
D. above

Air pumps are involved, but their role is limited _______ reducing resistance _______ the capsules' movement in the pipes.

A. to...to...
B. for...for
C. with...with
D. with...for

Capsules _______ up to 50 kg of goods could travel at 1500kph.

A. carry
B. carried
C. carrying
D. carries

You can wear _______ jeans in a few hours.

A. a
B. an
C. a pair
D. a pair of

You can take photographs with a new camera only a couple of hours after _______ your order.

A. place
B. places
C. placed
D. placing

中英文词组匹配