13. The pleasant feeling can strengthen your confidence in whitening your skin.
愉悦的以情可以增强你美白的信念。
还能这样说：
Having a good mood can bolster my belief to get a whitening skin.
The pleasant feeling can make you believe that your skin can be whitened.
应用解析：
whiten one's teeth 使牙齿洁白；
whiten cloth 把布漂白
14. It it a common sense that some vegetables are naturally cosmetic products.
某些蔬菜是天然的美容产品，这是一个常识。
还能这样说：
That some vegetables are natural beauty products is a common sense.
Certain vegetables are natural cosmetic ingredients, which is a common sense.
应用解析：
sixth sense 第六感，直觉；
stand to sense 有道理，合乎情理
15. Cosmetics have side effects.
化妆品有副作用。
还能这样说：
There are some side effects in cosmetics.
Cosmetics have harmful effects on skin.
16. Facial massage can whiten the skin.
面部按摩可以美白肌肤。
还能这样说：
Massaging the face can make your skin white.
Give a massage to the face can whiten the skin.
17. Before going out, please remember to daub sunscreen cream to protect your skin.
出门前涂抹防晒霜可以保护肌肤。
还能这样说：
To paint some sunscreen cream can protect your skin before you go out.
It will prevent your skin to smear sunscreen cream before you go out.