写一篇关于如何增强青少年免疫力的英语作文答:vitamin E is 50 times; 2 citrus biotin, from citrus, lemon extract; 3 polyphenols, is found in tea, olive oil, red wine; 4 soy isoflavones, present in certain mushrooms, fungus, with disease resistance, protect the heart, can activation of immune cells, balance the immune syste...