要不是有他帮忙，我们不可能取得成功。

要不是下雨，我们的旅行本来是很愉快的。(but for)

______ (要不是他们救了我们), we would have been drowned in the cold river.

__________(要不是有计算机), there would not have been man-made satellites or rockets.

________________ (要不是你帮忙)，I would not have finished the task by myself．