问题
选择题
求如图所示的交变电流的有效值,其中每个周期的后半周期的图象为半个周期的正弦曲线( ) A.5A B.5 C.5 D. ![]() |
答案
答案:C
求如图所示的交变电流的有效值,其中每个周期的后半周期的图象为半个周期的正弦曲线( ) A.5A B.5 C.5 D. ![]() |
答案:C
(2013·高考重庆卷,B)It is easy to overlook the role that your body plays in influencing your mood(情绪).When you are____,you may find yourself blaming work pressures or an unknown future.However,it could just be that you’ve been sitting behind your desk too long. One way to improve your mood is____.Psychologically,it provides you with a break from the stresses in your life.Also,in the process,you may aim for____goals,like a new personal running record or a better body shape.The achievement of a particular goal makes you feel good and contributes to your____.That is why exercise has been shown to____your selfrespect. You do not have to train yourself____to feel the psychological benefits of exercise.What really matters is____,not intensity(强度)of your exercise.You can try walking for 30 minutes five times per week or simply gardening on weekends.
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