I'm a non-native speaker of English and the following sentence makes me wonder:
"I won't stay longer than I can help."
I've heard similar uses of "can help" in other contexts and they all sounded strange to me. Shouldn't we say :
"I won't stay longer than I can't help."
In the same manner, doesn't it sound strange to say:
"I'm not driving at night, unless I can help it"
Shouldn't one say "unless I can't help it"?