Listening is just as ______ as speaking in language learning.
A:important
B:more important
C:most important
D:the most important
电影《甲午风云》中的主人公(如图)感动了许多人,他是( )
If he ____ (not tell) me what the problem is, I can't help him.
若存在实数x使x-a+x-1≤3成立,则实数a的取值范围是( )