对同一种流体而言，其密度随温度和压力的变化而变化。（）
参考答案：对
__from Adelaide to Darwin and you’ll observe some of Australia’s most beautiful landscapes.
A．Traveling
B．To travel
C．Traveled
D．Travel
Next door to ours _____, who has just retired from work.
A．where lives an old man
B．where does an old man live
C．lives an old man
D．does an old man live
