Yesterday I came across this sentence:
このえいがは、十八才以上しか見れません, and it just seemed very counterintuitive. Jisho tells me that しか means “only”, so I read the second part as
“18 higher than only cannot see”
…meaning only 18+ people CAN’T see this movie, i.e. the opposite of what it actually means. Could someone please help me clarify the usage of しか + negative verbs?