农民负担

地球表面海洋面积与陆地面积所占比例约是（　　）

A．7：3

B．3：7

C．71：100

D．29：100

传输延时确定的网络拓扑结构是

A．网状拓扑

B．树型拓扑

C．环型拓扑

D．星型拓扑

My parents often______ me some gifts on my birthday.

A．buy

B．will buy

C．buys

D．has bought

最易导致外伤性关节脱位的是

A．肩关节
B．腕关节
C．髋关节
D．膝关节
E．踝关节

Roll-on/roll-off ships are equipped with（）.

A.cargo elevators

B.conveyor belts

C.ramps

D.derricks and winches for cargo handling