粗细均匀的电热丝放入一壶水中，通电一段时间将水加热至沸腾．若将电阻丝对折并联后放入同样一壶水中，通电到将水加热至沸腾．所需时时间与第一次的通电时间相比 （电源电压恒定，不计一切热损失）．下列判断正确的是（　　）

—It's about 5         flight.

下列化学符号与其意义相符的是(  )

    Hi, good morning. My name is Wang Xu and I'm1student of No.8 Middle School. This is our2.It's new and big.3the library, you can4books everywhere, but it is still very5.We Call read books and do our homework(家庭作业)there.6the desks and chairs? They are on the second (第二) floor of the library. Look! That7is Linda. She is a friend of 8 .She likes reading and she is a good student. I think she is like my 9 because she often10me study English.