$\frac{\sin 7°+\cos 15°\sin 8°}{\cos 7°-\sin 15°\sin 8°}$的值为

①历史       ②科学         ③典礼仪式        ④社会情况

    Memory(记忆) is very important. It helps you remember who you are, where you live, what you have learnt and what you plan to do in the future.____ 

    Memory has close relationship with the brain(大脑).____ For example, you can do new things. If you walk a different way to school or take a different bus. You will keep your brain active. You can try to remember something new. You can try to learn new skills.____ Your brain gets lost of regular exercise if you do any of these things.

    If you live a healthy life, your memory will work better. You must have a balanced diet(均衡饮食)not just fast food.____ Unless(如果不)you get enough sleep every night, you will not remember things well.

    ____ If you get too worried, your brain will slow down, and your memory will become less sharp. So, to improve your memory, you should exercise your brain, live a healthy life and stay relaxed.

阅读下面方框中的五个选项（ABCDE），从中选出可以填入空白处的最佳选项，并将其标号填在相应的横线上。

在一艘做匀速直线运动的游轮上，某同学朝各个方向用相同的力进行立足跳远，则下列说法中正确的是    (    )

Please____(drink)more water every day.