chūfā qián ， tāmen zài wǎngshàng chá le tiānqìyùbào ， yòu qù chāoshì mǎi le zhàngpéng 、 shuìdài 、 shuǐ hé yīxiē língshí 。

出发前，他们在网上查了天气预报，又去超市买了帐篷、睡袋、水和一些零食。

Before leaving, they checked the weather forecast online and bought a tent, sleeping bags, water, and snacks at the supermarket.