Examples:

 Expressing opinions: I agree/ disagree with the above statement that 

·        In my opinion

·        I believe that

·        I am in favour of

·        I am against the idea of

·        It seems to me that

·        I sympathize with

Presenting and contrasting opinions: The main argument in favour/ against is 

·        It is often said that

·        First of all I should like to consider

·        Apart from that

·        Even though

·        Furthermore

·        In addition

·        Moreover

·        Nevertheless

·        And

·        Or

·        But

·        Finally

·        Lastly

·        Despite the fact that/ In spite of

·        On the other hand

·        On the contrary

·        Whereas

·        What is more

·        What matters most in this case is

·        It is a fact that

·        Besides

·        After all

·        There is no doubt that

 Reasoning: Because of 

·        As a result of

·        Owing to

·        Through

·        Due to

·        Consequently

·        On account of

·        Therefore

·        Hence

Concluding: To sum up 

·        To conclude

·        It can be concluded that

·        I believe that

·        Thus, I am of the opinion that

Argumentative verbs (use these instead of say/tell): 

·        Claim

·        Assert

·        Insist

·        Argue

·        Allege

·        Suggest

·        Point out

·        Maintain