How do you form the aorist tense in Greek?

The aorist tense can be formed in three ways: the weak aorist, the strong aorist, and the root aorist. All have an augment. The weak aorist has the same stem as the present tense + σ + endings (α, ας, ε, αμεν, ατε, αν). The strong aorist is formed from the aorist stem of the verb , e.g. λαβ- from λαμβανω, + the imperfect endings (ον, ες, ε, ομεν, ετε, ον). The root aorist is very rare and is formed from just the root of the verb, e.g. βη- from βαινω, + the person endings ν, σ, _, μεν, τε, σαν.