蒸汽喷射器扩压器内，蒸汽和空气混合物进行的是（）。
A、绝热膨胀
B、多变压缩
C、绝热压缩
D、等焓膨胀
参考答案：C
On our journey to Australia last summer, our luggage was _____ at the customs. We were not allowed to carry food such as meat and vegetables.
A．looked through
B．gone through
C．seen through
D．got through
依照《建筑材料放射性核素限量》（GB6566—2001），对要求的各种放射性核素进行测量，必须在检验样品中天然放射性衰变链基本达到（）后。
