1,it must be pointed out that 必须指出的是2.it goes without saying that 毫无疑问的是3.when it comes to . some people suggest that 当问到.有些人认为4.the reasons are as follow .firstly.secondly.thiredly,原因如下,1...2.3...5.it must be keep in mind that .必须记住的是.6.sum up to,总结起来7.on my opinion as far as I am concerned .就我来说