Always keep smiling

永远

adv. from here to eternity; forever; in/for/to perpetuity; for always; for good;

保持

v. keep; maintain; preserve; retain;

微笑

n. smile

I will keep smile forever。我要永远保持微笑

我每天保持微笑

I keep smiling every day.

每天

adj. everyday;

保持

v. keep; maintain; preserve; retain;

微笑

n. smile;

同。