Useful pharses for introduction

Some people consider that...
It's generally agreed that ....
A common viewpoint is that ....
It is widely believed that....
Recent research has suggested that....
It is often argued that.....
Many people say that ...........

http://www.phrasebank.manchester.ac.uk/introductions.htm

Useful language from Green book

This essay will.......
give an overview of...
discuss....
try to explan the main reasons
argue that ...
put forward the...
weigh up the benefits and drawbacks of ...
consider the arguments for
try to answer/address the question of whether ....