先生はまた元気になった。

teacher; master; doctor; with names of teachers, etc. as an honorific; previous existence

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

again; and; also; still (doing something)

lively; full of spirit; energetic; vigorous; vital; spirited; healthy; well; fit; in good health

at (place, time); in; on; during; to (direction, state); toward; into; for (purpose); because of (reason); for; with; by; from; as (i.e. in the role of); per; in; for; a (e.g. "once a month"); and; in addition to; if; although

to become; to get; to grow; to be; to reach; to attain; to result in; to prove to be; to consist of; to be composed of; to succeed; to be complete; to change into; to be exchanged for; to play a role; to be promoted; to do ...