Undoubtedly, political and economic factors have played their part.

毫无疑问，政治和经济因素起了作用。

These sort of statistics are undoubtedly alarming.

毫无疑问，这类统计数据为人们敲响了警钟。

It is undoubtedly true that harder times are on the way.

毫无疑问，更艰苦的日子即将到来。