demonstration可數嗎

We were given a brief demonstration of the computer's functions.

有人向我們簡短演示了這種計算機的各種功能。

The police were much in evidence at today's demonstration.

在今天的'示威集會上警察隨處可見。

She walked me through a demonstration of the software.

她一步步地給我演示軟體。

There was a strong police presence at the demonstration.

示威現場有了大批警察。

The police are preparing themselves for trouble at the demonstration.

警察正在準備防範示威時可能出現的騷亂。