Sunscreen 防晒霜
I need to apply some sunscreen every time I am going out in summer.
夏天我每次出去的时候，我都需要涂些防晒霜。

SPF 防晒系数
Sun Protection Factor
An SPF of 30 means that you could be out in the sun 30 times longer before you get sunburned than you would be able to if you go out without sunscreen.
防晒系数30意味着，被太阳晒伤的时间是你没涂防晒被晒伤时间的30倍。

UVA rays 长波紫外线
Ultraviolet A
UVA doesn’t cause sunburn, but it really leads to darkening and aging.
长波紫外线不会导致晒伤，但会让皮肤变黑老化。

Water-resistant 不被水溶掉的
I like swimming in open water during summer so I have to get a water-resistant sunscreen.
夏天我喜欢在开放水域游泳，所以我必须得买个水性防晒霜。

Waterproof 防水的
Luckily, my backpack is waterproof, so my clothes didn't get wet.
真走运，我的双肩包是防水的，所以包里的衣服没湿。