Precipitates are usually collected by centrifugation at intervals.常常是用离心法分段收集沉淀的.Try to get into the habit of eating at least three small meals a day, at equally spaced intervals.尽量养成每天至少吃3顿小餐的习惯，而且每餐的间隔要相同。She began to ...
George struggled wildly, going under and resurfacing at regular intervals.乔治疯狂地挣扎，不断在水面上浮浮沉沉。Make a point of backing up your files at regular intervals.一定要定期备份文件。The cartridge must be replaced at regular intervals.弹药必须定时...