"Thinks" is Third-person singular simple present indicative form of the verb "think"
The present tense form of 'think' is 'thinks' for the third person singular (he/she/it) and 'think' for all other subjects.
The third form of "wait" is "waited."
The third form of the English word "receive" is "received".
The third form of the word "split" is "split." In English grammar, there is usually not a separate form for the third form, as it remains the same as the base form.
"Thinks" is the third-person form of "to think", which is a verb... so no, it is not a plural noun.
The third form of shine is shone.
The third person form of arrive is "arrives."
The third form of shrink(i.e. to minimize something in size or miniature things) is Shrunk
The correct form of speech for "thinks" is a verb. For example, "She thinks about the problem."
Chao only evolve twice, so there is no third form.
One third is already in it's simplest form.