将下面的结构和发育情况用线连接起来

大豆的白花和紫花为一对相对性状．下列四组杂交实验中，能判定性状显隐性关系的是（    ）

①紫花×紫花→紫花         ②紫花×紫花→301紫花+110白花

③紫花×白花→紫花         ④紫花×白花→98紫花+107白花．

按照税法规定，不管通过何种方式，只要发生交易行为就得纳税。这表明税收
①可以增加国家财政收入
②具有用之于民的本质属性
③具有强制性的基本特征
④依法纳税是公民的基本义务

在下面—段文字横线处补写恰当的语句，使整段文字语意完整连贯，内容贴切，逻辑严密。每处不超过15个字。

    谚语有云：“予人玫瑰，手有余香。”然而，①____，这样做是因为我们还没有认识到，给予是世界上最强大的力量，它对健康的好处超过你的想象。给予不仅能让人获得快乐、幸福的正面情绪，而且还能保护心脏，提高免疫力，降低抑郁和自杀风险，延长寿命等，总之，②____。其实，只要愿意，③____，你可以做慈善，帮助困难之人，你可以常怀感恩之心，谅解和尊重别人，你还可以绽放一个动人的微笑，说出一句由衷的赞美。

     Tom and Mike are good friends. They are good with children. They want to find jobs in summer vacation. This Friday Tom tells Mike that Sunson School Trip needs teachers to help with sports, music and computer. Mike is glad to know that.
    Tom can play basketball, volleyball, and he can swim. Mike can play the violin, the trumpet, the drums and the guitar, and he can swim,too. Tom and Mike like computers very much. Can they join Sunson School Trip?