一定要前面主詞是生物(第三人稱) 後面動詞才要+S嗎?

Except 1st and 2nd persons outside, we've the third and we use to add the (s).
In other words, reading the 3rd person singular "he""she" we see "has" "goes" "eats" "has""lives"
In other words, reading the 1st person singular " I" and 2nd person "You" we see "have" "go'.
The Grammar Rule on Person and Number:-
You have probably read about person in Grammar, and number in Grammar. The explanation below shows the conjugation of the verbs "have" and "go" in relation to person, number and tense and mood:-
In other words, reading the 3rd person singular "He","She", "It" we see "has" "goes" eg:-He goes to school (every day.) eg:-He has two white newspapers.He lives on white rice.He thinks nonsense!!! Also eg:-She eats an apple today.---She has a dog at school.-----She lives on cosmetics.

In other words, reading the 1st person singular "I" and 2nd person "You" we see "have" "go" for SIMPLE PRESENT TENSE.

大多數都如此
但 3單後的動詞不一定要+s喔!
如 1.go--goes do--does
2.have--has
不過 除了3單 複數可數名詞是複數也要+s喔!!
例如 They are my brothers. 他們是我的弟弟

That is impossible.

主詞是第三者單數（包括人或事物皆可）時，動詞的現在式（或助動詞）要配合一致：is/has/does....

是的

凡第一、二以外的主詞後面都要加S唷!
只有有一些動詞例外
Ex: go 變成 goes