试题详情

( )is the carriage of goods from place to place by air.

One of the properties of light is（ ）traveling in wave form as it goes from one place to another.

The ozone converter prevents damage to the air separation module from oxidation of the membrane mate

h is the ___ . A. vertical distance from the chart datum to the ocean bottom, plus the height of t

) is the place at a port ,airport or border where travellers’bagsare inspected to see if any goods a