承上阐述

330.To understand the truth(point/nature)of…，

it is important (necessary/essential)to examine(analyze/see)…

331.To get a sense of(better look at/better understanding of/full appreciation of)how(what)…，

we must(have to)turn first to(have a bird’s eye view of/make a close study of)…

332.To illustrate(prove/show)this point，

let me(us)consider(ask why/look first at/develop my argument)

333.A(n)study(comparison/example)of…，

perhaps，will make this point clear.