I can well remember that I was once asked to deliver a speech titled: “A Real Test in My Life” before the whole class at the age of 9!You can imagine how ____ (terrible) shy I was the moment I thought of that with so many eyes ____ (fix) upon me. I had no ____(choose) but to prepare for it, though. First of all, I was to draft the speech, which was just a piece of cake for me, a good writer. But the hard part____(lie) in my oral presentation from my memory---for to read from the paper was not allowed. The real moment began ____ I stood on the platform with my legs trembling and my mind blank. But my____(listen)were still waiting patiently without any signs of rushing me. Gradually I found myself back, giving out my speech with difficulty. After what seemed to be a hundred years, I found my audience applauding ----I made____! From then on ,my fear of talking before an audience ____(appear). Actually with my confidence building up, I now turn out to be a great speaker. Looking back, I know the greatest difficulty on our way ____ success is our fear. Overcome it ,____ we will be able to achieve our goals.

袁隆平爷爷利用普通水稻和一种野生稻培育出了高产而优质的超级水稻．他主要运用的育种方法是（　　）