A problem is in P if it can be solved quickly by a computer, and in NP if a solution can be verified quickly.
你看到了，但你没有观察到。
Technological innovation is the core driver for the sustainable development of fisheries. Without technological support, fisheries have no future.
解释：手指粗于胳膊， 胳膊粗于大腿， 病情必然很重。