Article in English: Sunscreens allow some of the sun's rays to penetrate, giving you some tanning action while shielding you from many harmful UVA and UVB rays. Before start sweating or swimming, wait about 15 minutes to give your sunscreen a chance to bind to your skin. Do not lay out between 10 a.m. and 4 p.m. The sun's rays are strongest during those hours, and you're more likely to get a sunburn. Start by laying out for 15 minutes and add 5 minutes or so per week. Your tan will progress more gradually, but you'll avoid getting burned.

Summary in Vietnamese:
Sử dụng kem chống nắng sunscreen thay vì sunblock. Chọn kem chống nắng chống nước. Tránh phơi da lúc nắng to. Phơi nắng theo lịch trình.