原文:Stop waving that thing around.别拿它晃来晃去的！
stop doing sth:停止干某事
Please stop talking loudly.
请不要大声说话。

原文:Stop it. You're scaring him.行了！你伤害他了！
be scared of doing sth:对某事感到害怕
I'm scared of the baseball.
我害怕（打）棒球。
这时没必要加个play，因为从意思上可以理解出笔者是害怕打棒球。
be scared to do sth:害怕做某事
I'm scared to play baseball.
我害怕打棒球。

原文:I bet he's hungry.他一定是饿了。
bet+(that):敢断定,确信
I bet (that) you'll win.
我肯定你会赢。

food chain:食物链
lactate:分泌乳汁