Body language is of great importance to humans. We carry many of the meanings through body movements. However, many forms of body language we consider to be fine in our country can get us into trouble in other parts of the world.

　　A smile is one of the most common examples in different countries. While Americans smile freely at strangers, in Russia this is considered strange and even impolite. In Asian countries a smile isn't necessarily an expression of joy but it can be used to express pain.

　　The acceptable physical distance is another major difference. In Latin America and the Middle East the acceptable distance is much shorter than what most Europeans and Americans feel comfortable with. Hand and arm movements as a form of body language are also very different among countries. Handshakes are usually acceptable almost everywhere, even between strangers; however, kissing on the cheek and touching on the shoulder or other body parts aren't. For many people in Asia and other parts of the world, such actions are seen as a violation (侵犯)of one' s personal space. This is why you should not touch others easily.

　　Eye contact(目光接触)is one of the forms of body language where the differences are most striking. In America and Latin America looking the other person in the eye is a sign of respect. But in Asian countries, prolonged(过长的)eye contact is especially rude, so you should try your best not to do that.

What does striking in the fourth paragraph most probably mean?(　　)