Sentence examples for proved difficult to trace from inspiring English sources

Those landmarks surrounded her uncertain existence, which has proved difficult to trace.

In Koguryŏ and Paekche there may have been songs and a system of transcription corresponding to the hyangga and hyangch'al of Silla, but they have proved difficult to trace.

Shakespeare is known for borrowing plots and characters from other stories, but the source of A Midsummer Night's Dream has proved difficult to trace.

Historically it has proven difficult to trace the source that leads to an outbreak.

The advice proved difficult to follow.

Spectacular early results proved difficult to sustain.

Neutrality proved difficult to maintain, though.

Alas, it proved difficult to find.

Genocide has proved difficult to prosecute.

The effect proved difficult to measure.

The latter aim proved difficult to enforce.