1

我们

wǒmen

we; us; ourselves; our

2

认为

rènwéi

to believe; to think; to consider; to feel

=3

这不

zhèbu

(coll.) As a matter of fact, ... (used to introduce evidence for what one has just asserted)

=3

这不

zhèbù

connects two clauses, emphasising how the following clause substantiates the preceding clause

4

严肃

yánsù

(of an atmosphere etc) solemn; grave; serious (of a manner etc) earnest; severe; exacting to strictly enforce