quEstions 27—30 ArE BAsED on thE pAssAgE ABout sign lAnguAgE. you now hAvE 20 sEConDs to rEAD quEstions 27—30. whiCh oF thE Following wAs not usED By nAtivEAmEriCAns to mAkE A signAlA、smAll horsE.
B．CigArEttEs.
C、A、mirror.
D．FirE Arrows.