sit [stand] bolt upright
まっすぐに座る[立つ]
sit by
そばに座る
sit by [across from] a person
人のそば[向かい側]に座る
sit by [at, in] the window
窓際に座る
sit cross-legged
あぐらをかいて座る
sit [lie] down
座る[横になる]
sit down at the negotiating table
交渉のテーブルにつく
sit down on a corner of the sofa
ソファーの隅に座る
Sit down there, and thaw out.
そこに座って体を温めて
sit down to [for] dinner
夕食の席に着く(◆toだと食事を始めるという感じ)