选出与汉语意思相符的一项。

There are many insects in the world that never do _______ harm to human beings.

From what she has done we can predict that she is ______enough to make up her own decision and behave in a proper way.

 Polar explorers have to be extremely _____ to bear the climate and other hardships. 

He is at least as tall as his brother,  if not_______ ．