抛物线y=x2﹣（m+1）x+9与x轴只有一个交点，则m的值为____ ．
—Many students don't know how to____ stress and become worried.
—I think they should ask their parents for help.
食物中缺乏下面哪类物质可引起夜盲症（ ）
I didn't say that I wanted to buy it but ____(仅仅，只不过) asked for the price.
