后悔
惋惜
为……感到遗憾（regret的现在分词）

Regret \Re*gret"\, v. t. [imp. & p. p. {Regretted} (-t[e^]d); p.
pr. & vb. n. {Regretting}.] [F. regretter, OF. regreter; L.
pref. re- re- + a word of Teutonic origin; cf. Goth.
gr[=e]tan to weep, Icel. gr[=a]ta. See {Greet} to lament.]
To experience regret on account of; to lose or miss with a
sense of regret; to feel sorrow or dissatisfaction on account
of (the happening or the loss of something); as, to regret an
error; to regret lost opportunities or friends.

Calmly he looked on either life, and here
Saw nothing to regret, or there to fear. --Pope.

In a few hours they [the Israelites] began to regret
their slavery, and to murmur against their leader.
--Macaulay.

Recruits who regretted the plow from which they had
been violently taken. --Macaulay.