既可把它作为介词，亦可作为不定式符号。
1.有...的倾向(to为介词）
Modern furniture design tends to implicity.现代家具设计越来越简单
2. 倾向于tend to do sth.(有助于,易于,引起,造成,势必)
例句:
It's probably not as bad as she says she does tend to pile it on.
大概不像她说的那麽糟－－她确实有意夸大事实。
He's a good salesman, but his offhand manner does tend to put people off.
他是个很好的推销员，可是他那随便的态度容易使人产生反感。
Does he tend to lose?
他常常输吗?