acrobatics

要根據句意及上下文來確定謂語動詞用單數還是復數.

如籠統地表示"雜技"這門技藝,就用單數, 如:

Acrobatics is very hard to learn.

雜技非常難學.

如表示雜技表演, 則用復數,如:

His acrobatics yesterday were thrilling. 他昨天的雜技表演十分驚險.