蘑菇经常出现在森林中，但是它却不是植物，原因是（　　）

    Tom and Mike had a very good time last Sunday.That morning，they1at six o'clock and dressed(穿衣)themselves.2having breakfast，they went to the park.It's in the centre of the city. In the park.there were a lot of nice flowers.Mike wanted to 3one，but Tom stopped(阻止)him.He told Mike it was not.4to pick flowers.Then they went to the lake.By the lake,they saw a small5.They jumped into it and started a tour on the lake.Two hours6,they left the lake and walked up the hill(小山)near the lake.They got to the top at half past eleven.There they had their lunch.7did they have for lunch?Eggs，bread and oranges.In the afternoon,they 8home.When their mother asked them about the morning，9answered，"It was great.We10ourselves(我们自己)all the morning."

如图，甲、乙两渔船同时从港口O出发外出捕鱼，乙沿南偏东30°方向以每小时10海里的速度航行，甲沿南偏西75°方向以每小时10 $\sqrt{2}$ 海里的速度航行，当航行1小时后，甲在A处发现自己的渔具掉在乙船上，于是迅速改变航向和速度，仍以匀速沿南偏东60°方向追赶乙船，正好在B处追上．则甲船追赶乙船的速度为____海里/小时？

—Which is more useful, reading or writing?

—I think _______ of them are useful.