前面不加a，例如：

1、The insect's wings are almost transparent.这昆虫的翅膀几乎是透明的。

2、Honeybees use one of the most sophisticated communication systems of any insect.蜜蜂之间所用的交流方式是昆虫中最为复杂的方式之一。

3、The roof timbers were affected by rot and insect attack.屋顶的木料已经腐朽并遭虫害。