根据句意，用括号中所给单词的正确形式填空，每空一词。

1. So far, I have't made a             (decide) about where to go for the coming summer holidays.

2. This year it has rained so             (heavy) in South China that lots of problems are caused.

3. When we walked past the playground yesterday, we found him            (lie) on the grass, enjoying the sunset.

4. Jack is busy preparing for a party to celebrate his sister's             (twelve) birthday. He wants to give her a

    big surprise.

5. —On April 14th, an earthquake hit Yushu and destroyed its             (beautiful) completely.  —It's a great pity.

化学教师在引导学生探究金属钠与水的反应原理时，采用了实验探究教学模式：创设情景→发现问题→M→验证假说→得出结论→交流与应用；其中M是指______。

A．科学与抽象
B．实验设计
C．提出假说
D．创新思维