Her arrival coincided with our departure.
她来到时我们正好离开.
If the roads are icy, you'd be better advised (ie it would be more prudent) to delay your departure.
要是路上结冰了, 你最好考虑延期出发.
Their departure just before the floods was providential.
他们恰在发洪水之前离开, 走得真是时候.
