to tackle a problem

at first sight

to have difficulty in

a problem that cannot be ignored

the solution is far from obvious

the crucial point of this discussion

the extent of the consequences

given that

considering that

in view of

other factors have to be taken into consideration

people tend to believe

changes in the public opinion

it is worth to mention that

on the whole

not so long ago

the image shows, what i think to be

like the text suggests

the text highlights that

i am not in a position to say if that is true

I have the idea that