Ago, agere, egi, actum is a verb with many different idiomatic uses. Among the most common are agere + a time word, which means to pass or spend whatever time you are referring to. So, agere vitam would mean to spend one's life gratias agere, to give thanks.
Duc - 2nd Person, Singular, Present, Active, Imperative. More information on irregular singular imperatives of the third conjugation, along with a mnemonic device.
Come, come! Help me! Lead me to my second son!
Terence was a Roman Comic writer who wrote in the manner of Menander what is called New Comedy: a comedy of manners about life's problems, father's and sons, parties and good old Roman severity.
14. Non vitae, sed scholae, discimus.
Vitae and scholae are both datives of purpose. By using a dative of purpose, you can describe what use something is, what the end in view is, what function it is meant to have. Here is another example: poeta mihi venit amatori. (The poet came to me to be my lover.)
It isn't for life that we learn, but for school.
Seneca was a stoic philosopher. This statement should not be taken as a statement of how the world should be, but of how it is, but should not be.