happy as a clam

和蛤蜊一样快乐--非常快乐

Tom: I think my girlfriend really likes Hello Kitty.
Steve: Why do you say that?
Tom: When she sees Hello Kitty she's as happy as a clam.
Tom: 我觉得我的女朋友很喜欢Hello Kitty。
Steve: 你为什么这样说呢？
Tom: 每次她看到Hello Kitty都非常高兴。