acrobatics作主语,谓语动词用单数还是复数

　 acrobatics 是单复数同形,

要根据句意及上下文来确定谓语动词用单数还是复数.

如笼统地表示"杂技"这门技艺,就用单数, 如:

Acrobatics is very hard to learn.

杂技非常难学.

如表示杂技表演, 则用复数,如:

His acrobatics yesterday were thrilling. 他昨天的杂技表演十分惊险.