那个男孩儿很聪明.

That boy has good brains.

That boy is smart.

That boy is intelligent.

Source: Tatoeba

that one
that thing
that (as opposed to this)
(used before a verb or adjective for emphasis)
(used to humorously or indirectly refer to sth embarrassing, funny etc, or when one can't think of the right word)
(used in speech as a filler, similar to "umm", "you know" etc)
(euph.) menstruation
sex
also pr. nèige

very; quite
(also, often used before an adjective without intensifying its meaning, i.e. as a meaningless syntactic element)