Chewing is a very natural dog behavior that often starts in puppyhood when a dog starts to teethe .

咀嚼是很自然的狗的行为，往往始于青年的自大时期当狗开始长牙齿。

Checking of hearts is very important every time a dog visits a vet as many times the problem occurs later in life and not in puppyhood.

心脏检查是非常重要的狗每次访问一个时代的许多兽医问题发生以后的生活，而不是在青年的自大时期。