—Excuse me, sir, visiting hours are over. You leave.
—Pardon me, nurse. I didn't hear the bell.
A:may
B:can
C:must
D:need
A dog will love you faithfully and bring you ______ happiness for years.
有关环境人口容量的叙述,正确的是( )
读“不堪重负的地球”图,完成下题.