如血液碳酸氢盐和碳酸的值以同样倍数上升，动脉血的pH将（） A.保持不变 B.略有升

用方框里所给的单词的适当形式填空，使文章通顺、连贯、合理

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Every person needs friends. Friends are 小题1: who open their hearts to us. They always encourage us to try our 小题2: to do everything, and they even make us face challenges bravely.   小题3:  in touch with our friends is important to us all. In this way, we can know how everything is going on with our friends. Friends communicate with each other in different ways. Some make phone calls to their friends   小题4: . Some send postcards to their friends when they go on holiday. Others prefer to send interesting articles and小题5:  along with their letters. Among the ways, there must be your favorite one. Anyway, let’s communicate with our friends as often as possible.