occasionally名词

名词形式是occasion，例如：

1.Foreign visitors help to give a truly international flavour to the occasion.外国客人使这个场合显出一种真正国际性的气氛。

2.It happened on three separate occasions.这事在三个不同的场合发生过。

3.They have been seen together on two separate occasions.他们有两次被人看见在一起。