【C5】A．signalB．demonstrationC．symbolD．indication

A．guideB．modelC．symbolD．direction

【C5】A．verifyB．confirmC．indicateD．dictate

A red light is often used as a danger _____.A. signalB. signC. warningD. reminder

Many people like white color as it is a _______ of purity.A. signB. signalC. symbolD.

【C4】A．directionB．guideC．symbolD．model

【C4】A．signalB．signC．sighD．assign