同一批号浓度的质控品，血糖在A实验室20天测定结果的标准差(S1)为0.4mmol/L，B实验室20天测定结果的标准差为(S2)为0.3mmol/L。对于血糖的变异度，下列哪项是正确的()

A．A实验室大于B实验室

B．A实验室小于B实验室

C．A实验室等于B实验室

D．A实验室和实验室难以比较

E．需要用其他的统计量描述

Do you like travelling? Do you often travel in your holidays? Travelling is i__________ and exciting, but it is not if you get sick. So what can you do to stay in good h_______? There are three things you should remember when you travel: relax, sleep and eat w______ .

When you travel, there are so many places to v_______: museums, shops and parks. You may spend most of your days w_________ around these places. You may be very tired after a few h_________. If this is the way you feel, you should take a good rest.

Sleep is a________ important. You may want to stay out late at night. In many cities, the nightlife can be very exciting. Then you should plan to sleep for an hour in the day.

Finally, if you want to stay healthy, you must eat well. That m_________ eating the right kinds of foods. When you are in a new country, you may want to try new foods, but you need to be careful about how m_________ you eat . Lots of rich (油腻的)food isn’t good for you .