A whale is a mammal, and it breathes through its lungs. So once in a while _____ to the top of the water for air.
举一反三
- The small air sacs in the lungs through which gases are exchanged between the atmosphere and the blood are the __.
- How is rabies transmitted A: through the bites of rabid animals B: through direct contact C: through water D: through the air
- Through exposure to air, water, and organic matter, rocks _____ changes known as weathering.
- Air pollution is becoming worse. As is known to all, air to us is ________ water to fish. No one can imagine how human being can live without air.
- The compressed air is admitted to each cylinder through a cam operated by starting air valve when the piston has just passed its （）.