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    My name is Zhao Kai. This weekend I plan a dream day. I will get up very late. After I wash my face , I am going out to 1  morning exercises. At about 8:20 a. m., After I eat my 2, I am going to a shopping centre  3   my mother. The shopping centre is 4our home, so we will walk there. It 5 us about 20 minutes to get there on foot. The shopping centre has a good  6 . It is called "新兴购物中心" in Chinese. It doesn't have an  7   name. Can you help to put it into English? It is new  8  big.      9  many things there, such as TVs, fridges, bikes, computers, clothes, books, food and drinks. There are many   10  there. There are men and women, old and  11  . Parents must  12 their children. The shopping centre is so big. Young children may get lost in it. 13do many people come here to buy things? Do you know? Let me tell you. The things there are good and14 . The workers there are nice and friendly. If you come to my home, I can take15 there and have a look.

图是汽车启动装置电路简图，当钥匙插入钥匙孔并转动时，电磁铁得到磁性，此时电磁铁上端为 ____极，触点B与C ____(填“接通”或“断开”)，汽车启动。

某一池塘中有三个优势种群，分别是鳙鱼、浮游动物A和浮游植物B，其中鳙鱼以浮游动物A为食，浮游动物A以浮游植物B为食。回答下列问题：

函数$y=\sqrt{x}-1$中，自变量x的取值范围是　____ 　．

某种微生物合成的蛋白酶与人体消化液中的蛋白酶的结构和功能很相似，只是热稳定性较差，进入人体后容易失效。现要将此酶开发成一种片剂，临床治疗消化不良，最佳方案是（   ）