1、毫無疑問......
There is no doubt (that)...
例句：There is no doubt that complacency is the enemy of study.
毫無疑問，學習的敵人是自己的滿足。
2、根據(jù)我個人經(jīng)驗......
According to my personal experience, ...= Based on my personal experience, ...
例句：According to my personal experience, true mastery of any skill takes a lifetime.
根據(jù)我個人經(jīng)驗，對任何技能的掌握都需要一生的刻苦操練。
3、隨著人口的增加......
With the increase/growth of the population, ...
隨著科技的進步, ......
With the advance of science and technology, ...
With the rapid development of China's economy, a lot of social problems have come to pass.
雖然中國經(jīng)濟的快速發(fā)展，很多社會問題也隨之產(chǎn)生了。
4、......是必要的
It is necessary that ...
...是重要的
It is important/essential that......
...是適當?shù)?br> It is proper that......
...是緊急的
It is urgent that ......
5、.......的主要理由是......
The main reason why ... is (that)
例句：The main reason why the juveniles commit crimes is that social environment is becoming worse.
青少年犯罪的主要理由是社會環(huán)境日一敗壞。
6、俗語說得好...
Well goes an old saying,"…"= As an old saying goes(runs, says), "…"= An old saying goes, "…"
例句：As an old saying goes, "don't put off till tomorrow what should be done today."
俗話說的好，今日事，今日畢。
7、據(jù)說......
It is said (that)...
一般認為......
It is thought (that)...
大家都知道......
It is known (that)...
據(jù)報道......
It is reported (that)
預料......
It is expected (that)...
估計......
It is estimated (that)...
相信......
It is believed (that)...
例句：It is believed (that) nothing is difficult to the man who will try.
相信世上無難事，只要肯登攀。