1.今晚没有必要把所有的实验做完.
It's not necessary/unnecessary to finish all the experiment. tonight.
2.离开实验室时一定要把电源关掉.
Make sure that all the lights have been turned off when you leave the lab.
3.以我的看法,这本书值得一读.
In my opinion, this book is worth reading.
4.毫无疑问他是这份工作最好的人选.
It goes without saying that he is the most suitable person for the job.
Without doubt, He is the most suitable person for the job.
5.事实证明爱因斯坦是一位杰出的科学家.
Facts have proved that Einstein is an outstanding scientist.