they don't die because of the tumour.通常不會死于這種腫瘤

because of:因為； 由于

The game was cancelled because of the rain.

比賽因為下雨而取消了。

Scientists knew that the hypothalamus was involved in switching the appetite on and off.科學家知道下丘腦與調控食欲有關

involve in:卷入； 陷入

I got involved in a quarrel about the price.

我被卷入了一場有關價格的爭吵。

switch on:(用開關)開啟

The video is programmed to switch on at ten o'clock.

電視機設定在10點鐘自動打開。

switch off:(用開關)關掉

Do you mind if I switch the radio off?

我可以關掉收音機嗎？

Researchers spent ten years comparing this mutant mouse with other thin mice.科學家花了十年的時間來將這只基因突變的老鼠和其它瘦老鼠對比

compare with:與 ... 相比

Compare with those who is suffering, we are better off.

跟那些受苦的人相比，我們過得很好了。

How does your bike compare with mine?

你的自行車怎么能和我的自行車相比呢?