kàn dào dēng jī kǒu hòu xiān gū suàn bù xíng shí jiān zài jué dìng yào bù yào mǎi dōng xī

看到登机口后，先估算步行时间，再决定要不要买东西。

After seeing the boarding gate, first estimate the walking time, then decide whether to buy something.