意：a reason for having particular feeling or behaving in a particular way.
例：High unemployment rates are cause for worry.
Cause:名词，除了“原因”，还可以用来表示“理由”。可以在写作中=reason=grounds.
表“理由”时，是不可数名词，前面不能加a/an。最常见搭配有be/give cause for concern/celebration/alarm.
例：The early signals gave/are cause for both hope and worry.
经典句型：give cause for both hope and worry.(XX让我们喜忧参半）
例：Latin Americans are increasingly dissatisfied with politics in their countries. This is cause for worry.
例：The narrowing gap between bonds and stocks is grounds for anxiety, but not yet cause for alarm.
作业：
答：
1）
2）Users are increasingly discontent with the way that Internet companies treat their data. That gave cause for concern.
3) 情景：孩子两岁还无法讲超过50个词，让人十分担忧。
造句：My child could not say more than 50 words until two years old, which was cause for worry.
