单选题 Ever since human beings have inhabited the earth, they have made use of various forms of communication. Generally, this expression of thoughts and feelings has been in the form of oral speech. When there is a language barrier, communication is accomplished through sign language in which motions stand for letters, words, and ideas. Tourists, the deaf, and the mute (哑巴) have had to resort to this form of expression. Many of these symbols of whole words are very picturesque(生动形象的) and exact and can be used internationally, spelling, however, cannot.
Body language transmits ideas or thoughts by certain actions, either intentionally or unintentionally. A wink can be a way of flirting or indicating that the party is only joking. A nod signifies approval, while shaking the head indicates a negative reaction.
Other forms of nonlinguistic language can be found in Braille (a system of raised dots read with the fingertips), signal flags, Morse code, and smoke signals. Road maps and picture signs also guide, warn, and instruct people.
While verbalization is the most common form of language, other systems and techniques also express human thoughts and feelings.

单选题 Which of the following best summarizes this passage?

单选题 Which of the following statements is NOT true?

单选题 Which form other than oral speech would be most commonly used among blind people?

单选题 How many different forms of communication are mentioned in the passage?

单选题 Sign language is said to be very picturesque and exact and can be used internationally except for______.