在区间﹣1，1上随机取一个数k，使直线y=k（x+3）与圆x²+y²=1相交的概率为（　　）

与传统的有性杂交法相比，植物体细胞杂交的最大优点是（    ）

阅读短文，从A，B，C，D四个选项中，选出可以填入空白处的最佳选项。

    What do you do after class at your school? You may say you go 1 and do 2 homework. But I think we can have 3 other things to do after class.

    We can 4 different clubs, like the art club and the music club. What can you do? If you swim well, you 5 in the swimming club. Maybe(也许) you can't play the violin 6 the guitar well, but you can 7 to play them at the music club. 8, some people there can help you. I like books and I often go to the 9 club. Do you like books? Come 10 me.

下面划线词的含义与其他三项不相同的一项是（    ）

下列离子方程式中书写正确的一组是
①向明矾溶液中加入Ba(OH)₂溶液至A1³⁺ 刚好完全沉淀：
Al³⁺＋ SO₄^2－＋3OH^－＋Ba²⁺= BaSO₄↓＋Al (OH)₃↓ 
②氟气和水反应：2F₂＋2H₂O = 4H⁺＋4F^－＋O₂  
③向澄清石灰水中加入少量小苏打溶液： 
Ca²⁺＋OH^－＋HCO₃^－= CaCO₃↓＋H₂O  
④铜片投入稀HNO₃溶液：Cu+NO₃^－+4H⁺ = NO↑＋2H₂O＋Cu²⁺  
⑤钠与水反应：Na +2 H₂O = Na⁺ +OH^— + H₂↑
⑥碳酸钙放入盐酸中： CO₃^2- + 2H⁺ = CO₂↑ +H₂O
⑦向沸水中滴加FeCl₃溶液制备Fe(OH)₃胶体：Fe³⁺＋3H₂OFe(OH)₃(胶体)＋3H⁺
⑧过量氯水与FeI₂溶液作用： 2Fe²⁺ + 2I^—+ 2Cl₂ =" 2" Fe³⁺ + I₂ + 4Cl^—