Let the teacher give other verbs, and require the pupils to name and explain the different tenses.
I walk. Thou walkest. He walks. They walk.
In the second sentence, the verb walk was changed by adding est; and in the third, it was changed by adding s. These changes are for the sake of agreement with the person of the subject. The verb ending in est agrees with the subject thou in the second person, and the verb ending in s agrees with he in the third person. In the fourth sentence, the subject is in the third person; but it is plural, and so the verb drops the s to agree with they in the plural.
Verbs are said to agree in +Person+ and +Number+ with their subjects. The person and number forms will be found in Lessons 93, 94.
+DEFINITIONS+.
+Mode is that modification of the verb which denotes the manner of asserting the action or being+.
+The Indicative Mode asserts the action or being as a fact+.
+The Potential Mode asserts the power, liberty, possibility, or necessity of acting or being+.
+The Subjunctive Mode asserts the action or being as a mere condition, supposition, or wish+.
+The Imperative Mode asserts the action or being as a command or an entreaty+.