1. 同时;与此同时
    Meanwhile means while a particular thing is happening.

    e.g. Brush the aubergines with oil, add salt and pepper, and bake till soft. Meanwhile, heat the remaining oil in a heavy pan...
           把油涂在茄子上，加盐和胡椒烤至松软。与此同时，在厚锅中加热剩余的油。
    e.g. Kate turned to beckon Peter across from the car, but Bill waved him back, meanwhile pushing Kate inside.
           凯特转身示意汽车对面的彼得过来，可是比尔却挥手示意他回去，同时把凯特推进车内。

2. 在此期间;其间
    Meanwhile means in the period of time between two events.

    e.g. You needn't worry; I'll be ready to greet them. Meanwhile I'm off to discuss the Fowler's party with Felix.
           你不必担心，我会招呼他们的。其间，我还要去跟费利克斯商量一下福勒举办聚会的事。

3. (引出某一情形的另一方面，尤指与前面提到的完全相反时)与之相比，然而
    You use meanwhile to introduce a different aspect of a particular situation, especially one that is completely opposite to the one previously mentioned.

meanwhile

    e.g. He had always found his wife's mother a bit annoying. The mother-daughter relationship, meanwhile, was close.
           他总是觉得丈母娘有点烦人，然而她们母女之间的关系却非常亲密。