1. Even the boom that happens when the jet breaks the sound barrier went unnoticed.
    也察觉不到飞机冲破声障时发出的隆隆声。

2. The Sahara Desert is a natural barrier between North and Central Africa.
    撒哈拉沙漠是北非与中非之间的天然屏障.

3. The deep river was an insuperable barrier to those who could not swim.
    对不会游泳的人来说，这条深河是无法超越的障碍。

4. They had the English Channel as a barrier against the Nazi ground forces, and they had the Royal Air Force(RAF) to battle the Nazis in the sky.
    他们有着英吉利海峡这道抵挡纳粹地面部队的天然屏障，还有皇家空军在空中与纳粹作战。

5. High tariff is a barrier to international trade.
    高关税是发展国际贸易的障碍。