题目

现有M、N、P、E 4种元素的单质，能发生以下反应： ①在水溶液中，M＋N2+===M2+＋N ②P＋2H2O(冷)===P(OH)2＋H2↑ ③N、E相连浸入稀H2SO4中，电极反应为：N－2e-===N2+，2H+＋2e-===H2↑   判断它们的还原性由强到弱的顺序是 A．M、N、P、E      B．P、M、N、E C．M、N、E、P          D．E、P、M、N 答案：BWe have to agree that brushing teeth day after day can be a bit of pain. What’s even worse is trying to get much water to rinse(冲洗) out the toothpaste. Not only is it difficult, but also a waste of water. Of course, you could use a rinsing cup, but that has to be cleaned all the time. Now, a design company has finally invented an interesting invention called Rinser to help you do it.A company in New York recently invented a toothbrush. It looks very much like a common one expect one thing. That is when you pour water on the handle, it magically sprouts(涌向) straight into your mouth. It makes rinsing an easy thing and a lot of fun.The brush is designed such that its handle(把手) has a hollowed(空的) out part. This part collects tap water and directs it to a tiny spout(喷口). All the users have to do, is aim the tap onto the spout and the toothbrush will offer you water as much as possible.This kind of cool toothbrush won’t be used until November, 2012. Although it is convenient, it is a little expensive. Each one can cost $22 if you order it from the design company____it is sold in stores, the price will rise up to $34.99. If you are interested in this cool toothbrush, ask your mum or dad to get one for you!【1】What can Rinser do according to the passage?A. It can save time when you brush your teeth.B. It can help you rinse the toothpaste.C. It can help wash your face.【2】What does Rinser look like ?A. It looks like a common toothbrush.B. It looks like a tap.C. It is too heavy.【3】What does Paragraph 3 mainly tell us?A. It mainly tells us what Rinser looks like.B. It mainly tells us when we can use Rinser.C. It mainly tells us how Rinser offers you water.【4】When will people start to use Rinser according to the passage?A. In December 2012.B. In November 2012.C. In November 2013.