The situation is getting worse by the day.

情况一天比一天糟。

There's less and less water by the day.

每天的水越来越少。

Under pressure, both social and governmental, their numbers shrink by the day.

迫于压力，既有社会压力也有政府压力，这群人的数量总算日渐少了起来。

He's getting more paranoid about Dumbledore by the day.

他对邓布利多的疑心一天比一天重。

His facial appearance was changing by the day. His moods grew gloomier and gloomier.

他一天天消瘦下去，性格越来越忧郁。

Every evolutionary story he had touched became more complex by the day.

他曾接触过的进化的说法都日渐变得复杂起来。

They're getting trickier and trickier by the day. Last night was the big challenge.

随着时间的流逝，情况变得越来越复杂。昨晚是重大的挑战。

As the weeks went by, the days grew longer, the nights grew shorter.

几周之后，白天更长了，夜晚变短了。

He worked through the day by sunlight, and into the night by candlelight.

白天日光相佐，晚上烛光相伴。

The people who fled Sinjar are arriving in worsening conditions by the day.

这些人从辛贾尔逃来，自那时起处境就每况愈下。