the dog enters vs the dog enter

Some examples from the web:

• Let the dog enter.
• When someone enters a village, the dogs smell and bark to alert.
• That tells him when it's safe to enter the house, When she comes and goes, when the dog-walker comes, And what the combination to the house is.
• Zubrin is given to the dog once a day within 1-2 hours after feeding until the dog gets better.
• The dog defended his master from harm.
• The dog cannot distinguish between colors.
• Honey, I read the dog ladies' letter.
• Suppose a farmer shoots the dog next week.
• Guess he trained the dog with dummies.
• For easy application the dog should be standing.
• I am not taking the dog.
• The dogs are guests of the Animal Welfare Committee.
• And I still haven't found the dog you stole from me.
• The dogs started hunting in packs and threatening humans.
• MUNTZ: I'm sorry about the dogs.
• Cristian, take the dog outside.
• The dog was old, and the dog, the dog was sick.
• And what we're doing, in essence, is we're teaching the dog, kind of like - we're letting the dog think that the dog is training us.
• The strength of tablet to be given is based on the dog's weight, so that the dog is given between 1 to 2 mg per kg of the dog's bodyweight per day.
• The dog sees Jason and the next shot is the dog apparently jumping through the window.

Some examples from the web:

• Let the dog enter.
• When someone enters a village, the dogs smell and bark to alert.
• That tells him when it's safe to enter the house, When she comes and goes, when the dog-walker comes, And what the combination to the house is.
• Zubrin is given to the dog once a day within 1-2 hours after feeding until the dog gets better.
• The dog defended his master from harm.
• The dog cannot distinguish between colors.
• Honey, I read the dog ladies' letter.
• Suppose a farmer shoots the dog next week.
• Guess he trained the dog with dummies.
• For easy application the dog should be standing.
• I am not taking the dog.
• The dogs are guests of the Animal Welfare Committee.
• And I still haven't found the dog you stole from me.
• The dogs started hunting in packs and threatening humans.
• MUNTZ: I'm sorry about the dogs.
• Cristian, take the dog outside.
• The dog was old, and the dog, the dog was sick.
• And what we're doing, in essence, is we're teaching the dog, kind of like - we're letting the dog think that the dog is training us.
• The strength of tablet to be given is based on the dog's weight, so that the dog is given between 1 to 2 mg per kg of the dog's bodyweight per day.
• The dog sees Jason and the next shot is the dog apparently jumping through the window.