have difficulty doing做某事有困难

例句：They have difficulty setting boundaries.
      有困难定界限。

2.The shape depends mainly on the temperature and water levels in the air.

depend on依赖, 依靠

例句：You can't depend on your parents forever.
      你不能永远依赖你的双亲。

      You may depend on their support.
      你可依靠他们的支持。