Question

.A ________may be given ____means of flags, lights, and guns.

A．sign; by

B．signal; in

C．signal; by

D．sign; in

Answer 1

C

考查词义辨析。sign 符号，signal 信号，短语：by means of 以什么样的方式，句意：信号可以以红旗，灯光和发枪的形式给出。所以选C。