从方框中选用合适的词，并用其适当形式填空。

please

thin

hear

excite

they

An elephant has poor eyesight but good _________ and smell.
I went to HK for my holiday, and it was really a __________ trip.
Mother giant pandas often leave baby pandas for two whole days by _________.
Swimming is not as __________ as cycling.
He is as tall as his brother, but his brother is much _________ than he.