1. We must keep in mind that... 我们必须牢记…...
We must keep in mind that we are not children any more, and we should be independent.
2. It is said/reported that… 据说/据报道…...
It is reported that the building caught fire at 2 o clock in the morning, causing 30 people injured/and 30 people were injured .
3. It is believed/thought that... 人们认为…...
It is believed that music can help people relax themselves.
It is thought that music can help us reduce the pressure from study and life .
4. It is estimated that... 据估计…...
It is estimated that 70% of families in Dongguan have their own private cars.
5. It cannot be denied that... 无可否认.…..
It cannot be denied that great changes have taken place in China in the past 30 years.