4. squamous: Squamous cells are cells that are shaped like fish scales (= small flat pieces on the skin) （细胞）鳞状的

• Basal cell carcinomas and squamous cell carcinomas are the two most common types of skin cancer.

5. carcinoma: a cancerous growth that forms on or inside the body 癌；肿瘤

• Once a carcinoma has been detected should it be treated?

UVB causes sunburn, and is linked to particular types of skin cancer — basal cell carcinoma (the most common type) and malignant melanoma.

中波紫外线UVB会导致晒伤，并与特定类型的皮肤癌——基底细胞癌（最常见的皮肤癌）和恶性黑色素瘤有关。

Sunscreen doesn't stop all types of skin damage so for maximum protection, it's recommended to cover up and seek shade when the sun is strongest.

防晒霜并不能阻止所有类型的皮肤损伤，所以为了最大限度地保护皮肤，建议人们在阳光最强烈的时候遮光和寻找阴凉处。

The SPF number on a bottle of sunscreen refers to how much UVB it allows in, not how much it blocks. A sunscreen with SPF 15 allows one-fifteenth of the sun's rays to reach your skin, or about 7%.

一瓶防晒霜上的防晒系数是指它能吸收多少中波紫外线，而不是指它能阻挡多少中波紫外线。防晒系数为15（SPF15）的防晒霜可以让十五分之一（约7%）的太阳光线进入皮肤。

So it filters out about 93% percent of UVB rays while SPF 30 filters about 97%.

因此，它可以过滤大约93%的中波紫外线，而防晒系数为30（SPF30）的防晒霜可以过滤大约97%的中波紫外线。

This means if you could stay in the sun for 10 minutes unprotected without burning, SPF 15 would in theory give you 15 times that protection, or two-and-a-half hours before you'd burn.

这意味着，如果你在没有采取防护措施的情况下，待在阳光下10分钟皮肤没有被晒伤，理论上防晒系数为15（SPF15）的防晒霜可以把保护时间延长15倍，即在两个半小时后你可能会晒伤。