已知集合A={1,2,3}，$B=\left\{x\right|x^2-x-2=0,x\in R\}$，则$A\cap B$为 （   ）.

等差数列{a_n}和{b_n}的前n项和分别为S_n和T_n，且$\frac{S_n}{T_{{}_n}}=\frac{2n}{3n+1}$，则$\frac{a_5}{b_5}$ =    （   ）

    ____When it comes to your skin, there is an important fact that you must keep in mind: Your skin is the largest organ of your body. Therefore, skin health and protection is crucial. Your skin does everything for you. It can keep your body hydrated and regulate your body's temperature.

    Now, here are some helpful tips for you to protect your skin:

    ____Protection against harmful rays from the sun is one of the most important steps that you need to take. With this in mind it is necessary for you to avoid strong sunlight as often as possible. As for sunscreen you need to buy products that contain UVA-1, UVA-2 and UVB protection.

    ____Your diet also has a direct impact on the health of your skin. The most important aspect of your diet in relation to the health of your skin is to make certain that you eat a proper amount of food items that contain the proteins and nutrients necessary for cellular maintenance, repair and regeneration.

    ____Water is also important to the health of your skin. While you certainly have heard it before, it actually is true that you should drink at least eight 8-ounce glasses of fresh water every day. There are many health benefits to be derived from drinking water daily, including maintaining healthy skin.

    ____Finally, when it comes to the health of your skin today and into the future you should avoid smoking all together. In addition, you should drink alcohol only in moderation. Both smoking and excessive alcohol consumption can negatively impact the health of your skin in significant ways.

左图为抚顺某月21日—23日天气情况，右图为某区域21日海平面气压（hpa）分布图。