A few corrections 2

(a)The cobra has poisonous.

     The cobra ‘s teeth has poisonous.

     The cobra is poisonous.

(b) He gave an injection to Ali.

(c) During recess, they played (with) traffic games.

(d) The firemen talk about (the / a) fire prevention.

(e) They invited a traffic police to give a talk about (a/the) road safety.

(a)The cobra has poisonous. NO

     The cobra ‘s teeth has poisonous. NO

     The cobra is poisonous. YES

(b) He gave an injection to Ali.  YES

(c) During recess, they played (with) traffic games. No "with." I don't know what "traffic games" are, so I  don't know if you're saying what you think you are. To me it sounds like they played in traffic.

(d) The firemen talk about (the / a) fire prevention. No article. By putting this in the present tense, you are saying this do this habitually.

(e) They invited a traffic policeman (or woman) to give a talk about (a/the) road safety.