The influence of climate on crops are self-evident.
氣候對農作物的影響是不證自明的。（不可數）
What are the influences of TV ads on us?
電視廣告對我們的影響是什么？（可數）
News media have a great influence on people's mind.
新聞媒介對人的思想有很大的影響。
I don't want to influence you. You must decide for yourself.
我不想影響你。你必須自行決定。