Grammar exercises: How to use 倍 (bèi) in Chinese grammar: -times, -fold and multiplication 语法:倍 练习
The example sentences of the article, a few to an exercise, in the order the article shows them. Each exercise takes the point's word out of a sentence for you to fill back in, then gives you the sentence's words to put in order, and an item you miss comes back later in the same sitting.
2 grammar exercises over 14 items.