语音知识（共5小题；每小题1分，满分5分）
come

A．cold

B．cock

C．comfort

D．improve

dead

A．eager

B．great

C．least

D．health

united

A．use

B．ugly

C．upstairs

D．put

  ours

A．outside

B． cousing

C．nervous

D．clocks

thirty

A．theatre

B．thus

C．although

D．feather