For junior-high students, it should be "no more than an hour and a half", and two for high school students.

对于初中生而言应该是“不超过一个半小时”，对于高中生则应该是两个小时。

youdao

Most people spend about half an hour at a time, and two hours total.

大多数人一次性花半小时，分四次共两个小时。

youdao

Seattle is only a two and a half hour drive south and San Francisco is a two-hour flight away.

西雅图在这儿往南仅两小时半车程的地方，圣弗朗西斯科距此则是两小时飞机的路程。

youdao

And it can go from zero to ninety-five kilometers an hour in just two and one half seconds.

VOA: special.2009.11.03

During the two-and-a-half hour moon walk, the astronauts frolicked in the weightlessness of outer space and planted an American flag in the lunar surface.

VOA: standard.2009.07.16

Having sat through the two and half hour long Spice Girl themed musical Viva Forever, I am not surprised it has received generally poor notices.

BBC: Is Posh the real paragon of Girl Power?

Orbiting the Earth in a path that was inclined at 45 degrees to the equator, passing as close to 590 miles to the surface of the Earth, Telstar could be used for just twenty minutes out of each two and a half hour long orbit to relay signals between the America, France, and the United Kingdom.

FORBES: Telstar, the Fifty Year Old Hero of Communication

After a two and a half hour meeting in Inverness, Highland councillors voted to remove the curfew.

BBC: Highland nightclub curfew to be abolished