occurrence造句
The greatest
occurrence of coronary heart disease is in those over 65.
65岁以上者是冠心病的最高发人群。
For months at a time, air raids were a nightly
occurrence.
一度有几个月，每天晚上都会发生空袭。
The
occurrence of the disease is apparently related to standards of hygiene.
这种病的发生率显然与卫生状况相关.