それは最も重要な問題だ。

Meaning
that's the most important issue

Vocab used in this sentence

それ
it, that, there
a, the, is, am, are, will
最も
most, the most, best, least, farthest, extremely
重要
important, crucial, significant, essential, material, principal, big, considerable, meaningful, momentous
a, the, na, nan, nai
問題
problem, issue, matter, question, trouble
is, be, are, am, it is, seems

The developer Jeffrey van Binsbergen is known for his high quality work and optimalisations.