The pressure now was relentless.
压力现在没完没了。
The rain now was pelting down .此刻大雨滂沱
为什么用was?
now 也可以与过去时连用。如:
Now it was time for some food. 现在该吃点东西了。(转引自张道真《高级英语词典》)
Now she began to laugh. 这时她开始笑了起来。(同上)