题干

水稻高秆(D﹣易倒伏)对矮秆(d﹣抗倒伏)为显性,抗稻瘟病(R)对易感稻瘟病(r)为显性,两对相对性状独立遗传.用一个纯合易感病的矮秆品种与一个纯合抗病高秆品种杂交,F1自交得F2,F2代中出现既抗病又抗倒伏类型的基因型及其比例为(    )

A:RRdd, 18

B:Rrdd, 116

C:RRdd, 116 和Rrdd, 18

D:rrDD, 116 和RRDd, 18

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C

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    You have probably heard the saying,"When life gives you lemons,make lemonade."Since lemons are considered bitter and lemonade is considered sweet,the saying tells you to make the best out of a bad situation.

    Unfortunately,when something bad happens,it's not uncommon for most people to talk about it to anyone who'll listen,and complain about life,"Why me?"That's like getting a bag of lemons,putting them down,and thinking, "Lemons taste bad!I'd rather have chocolate!"If you don't make anything with the lemons,they will go bad.But what if you did something with them?What if you made lemonade?Isn't it possible to do something similar with a bad situation?

    Here's an example.Let's say you're about to go to the movies,but you discover you have a flat tire(瘪胎).You consider this a terrible thing. After all,you are really looking forward to spending some time with Ryan Gosling and Emma Stone.Now you're all stressed out,hating the tire,the car,and your life.But what if you called AAA,got your tire fixed or got caught up on things that you'd been meaning to do?What if you did some reading,or had coffee with a friend instead?A negative experience can be turned into something positive.Almost anything can work itself out into something better.You can't change what has happened,right?So make the best of it.I'm not saying it will be easy. The easy thing to do is complain about your bad situation and not consider what it could be turned into.

    Next time when some unfortunate things happen,stop and think,"How can I turn this around?How can I make it a positive experience?You needn't fear difficulties.As long as you keep on changing it,you will see the benefits(好处)at last.

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