The half-life of a reaction is time needed to consume half the reactant.

Half-life is the time for the concentration of a reactant decreases by half.

Red has become a main color in the film Red Sorghum, and the whole film is shrouded in red from the beginning to the end. In the first half of the film, red is the color of life, is the praise of life, full of the spirit and passion of the essence of life.

99. After wandering around nearly half his life, Alex finally __________down in Canada. A: decided B: determined C: settled D: set

The apple is too big , let’s cut it [u]         [/u] . A: in half B: to half C: into half D: at half

This doll is<br/>about ______high. A: a half meter B: half a meter C: half meters D: half meter

Hehasbeenherefor_____________. A: one and the half months B: one and a half month C: one and a half months D: one and the half month

It’s not a good habit to leave your work __________ . A: done half B: half done C: a half done D: done a half

He doesn't act ______ Tom ______. A: as half strangely as B: so half strangely as C: half strangely as D: half so strangely as

Many great discoveries were made in ____ the 19th century. A: the second of half B: second of the half C: the half second of D: the second half of