They could still invalidate Fourth Amendment protections when facing severe, urgent circumstances, and they could take reasonable measures to ensure that phone data are not erased or altered while a warrant is pending.
1.重点词汇及短语:
invalidate v. 使无效;证明(信念或解释)是无效的
severe v. 非常严重的;困难的
take reasonable measures to 采取合理的措施去……
warrant n. 令状,许可
pending n. 在等待……之际
2.句子成分分析:本句是一个由and连接的并列句。and前面的主干结构为They could still invalidate Fourth Amendment protections...。when facing severe, urgent circumstances是时间状语从句,由于face的逻辑主语与主句主语一致,因此省略主语和系动词,face用现在分词形式。and之后的句子主干结构为they could take reasonable measures...。to ensure that...pending是目的状语,that引导的从句作ensure的宾语。状语从句中的省略原则是:如果从句主语与主句主语一致,或从句的主语是it,可省略从句的连接词、主语和be动词,只保留分词和其它成分,从而使语言更加简洁明了。比如时间状语中的省略、地点状语中的省略、让步状语从句中的省略等。例如:The river is clean where (it is) deep.