【单选题】听力原文:O.K. Here's your key. The elevator is down the hall to your right. Breakfast will be served from seven to eleven a.m. in the restaurant, which is down the stairs. The fitness room is from eight a...
【简答题】能保证直线 a 与平面 α 平行的条件是 ( ) A . b ⊂ α , a ∥ b B . b ⊂ α , c ∥ α , a ∥ b , a ∥ c C . b ⊂ α , A 、 B ∈ a , C 、 D ∈ b ,且 AC ∥ BD D . a ⊄ α , b ⊂ α , a ∥ b