鲫鱼是一种常见的淡水鱼类．关于“探究鲫鱼适应水中生活特征”的实验结论，正确的是（ ）
—How _______ it is to spend the weekend at the seaside!
—Yes. Everyone will be _______ in the life there.
走进中学是我们人生的一个新起点。（ ）
His father bought iPhone 6s for his mother as useful gift yesterday．
