This paper tries to study spatial relations and their linguistic expressions from a cognitive point of view based on the spatial frames of reference and the Figure-Ground relations.

The principle of figure-ground segregation is one of the basic cognitive principles,it can be applied to language as well.

The nature of figure-ground reflects the principle that language obeys in time and space.

We will research on structural ambiguity caused by prepositional phrase in cognitive perspective with figure-ground theory.

According to its classification and based on the particular examples both in English and Chinese,selective question sentence is analyzed in terms of forming theory,prototype,figure-ground theory,perspective and other aspects,aiming to in some measure reflect the cognitive process of applying and understanding the language.

According to the properties of figure/ground, some principles of linguistics in space and temporal events are studied.

This paper attempts to study polysemy of when-complex sentences in the light of cognitive theories(metaphor and figure/ground)so as to explore the inner mechanism underlying their syntactic structure and tries to reveal the implication for foreign language teaching.