Marconi tied several antennas to kites.马可尼在风筝上系了几根天线.Radio astronomy today is armed with the largest antennas in the world.射电天文学拥有世界上最大的天线.The jet has 57 antennas for its huge array of electronic gear. Normal is 17.机上装有五...
Exercise dilates blood vessels on the surface of the brain.运动会使大脑表层的血管扩张。Standard measurements of blood pressure are an important but crude way of assessing the risk of heart disease or strokes...标准的血压测量是评估患心脏病或中风几率的一个重要...