Canst

Let this little book be thy friend, if, owing to fortune or through thine own fault, thou canst not find a dearer companion.

Source: tatoeba (4603753)

To thine own self be true, and it must follow, as the night the day, thou canst not then be false to any man.

Source: tatoeba (6101054)

And he brought him forth abroad, and said to him: Look up to heaven and number the stars if thou canst. And he said to him: So shall thy seed be.

Source: tatoeba (7848784)

But he said: The thing thou dost is not good. Thou art spent with foolish labour, both thou, and this people that is with thee; the business is above thy strength, thou alone canst not bear it.

Source: tatoeba (8079647)