单项选择题

The deep-sea listening system makes use of______.

A．the sophisticated technology of focusing sounds under water
B．the capability of sound to travel at high speed
C．the unique property of layers of ocean water in transmitting sound
D．low-frequency sounds travelling across different layers of water

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单项选择题

For Asians, the comfortable zone______.

A．is deliberately determined
B．measures 21 inches
C．varies according to status
D．implies esteem

单项选择题

What does the passage mainly concern

A．It concerns distance and bodily contact.
B．It concerns body language.
C．It concerns cultural differences between the East and the West.
D．It concerns hand signals.