原因类：
1) because …
2) because of …
3) due to …
4) since …
5) as …
6) for …
7) The reason is …
8) That‘s why …
9) By reason of …
10) Owing to …
结果类：
1) so …
2)so that …
3)therefore …
4)thereby …
5)hereby …
6)thus …
7)As a result
8)consequently …
9)hence …
10)accordingly …