As no pumas had been reported missing里面的had been能不能换成was呢?

As no pumas had been reported missing里面的had been能不能换成was呢? no pumas had been reported missing ZOO后为什么不加S As no pumas had been reported missing from any zo 新概念英语第三册第一课有句话：“As no pumas had been reported missing from a As no pumas had been reportedmissing from any zoo in thecoun 英语句子不理解no kangaroo had been reported missing from any local No kangaroo had been reported missing from any local zoo.这里m 请教前辈一个英语问题 As no puma had beed reported missing f had been 是 was 的过去式吗 was done和had been done的区别 The cake was excellent ,____ A as had been the coffee B as w had been的否定形式