Water under the bridge:
桥下的水 ×
岁月流逝 √
例句:
Don't worry about it. It's water under the bridge.
没关系,都已经过去了。
Low-hanging fruit:
挂得很低的水果 ×
容易实现的目标 √
例句:
We first need to sell this new product to our current customers. They are low-hanging fruit.
我们首先要把新产品卖给我们现有的客户,他们是我们绝佳的机会。