Since all cats are mammals and some mammals are not dogs, it follows that some cats are not dogs.

If A is greater than B and B is greater than C, then A must be greater than C.

Although penguins are birds, they are an exception and cannot fly.

Since all squares are rectangles, it is possible that some rectangles are squares.

Since every student in the class passed the exam and John is a student, we can conclude that John passed the exam.

If the office is open, then it cannot be a holiday, as the office would be closed on holidays.

If it rains, the ground gets wet. Since it is raining, we can conclude that the ground is wet.

Since some fruits are apples and all apples are sweet, it follows that some fruits are sweet.