大多数蘑菇是完全无害的，但有些是有毒的。

Most mushrooms are completely ___harmless, but some are poisonous.

总之，汽车并不像看起来那么无害，所以我们必须减少使用它们。

In conclusion, cars are not as ___harmless as they look, so we must stop using them so much.

这种化学物质对人类无害，但对昆虫有毒。

The chemical is ___harmless to humans but toxic to insects.