Is generally used when either 1 or each of the options might be true. Consider the following a few examples: That's why expressing "I don't think that is often a problem" is fine - as long as you happen to be common with this particular use from the term "that". https://cesarxcska.blog-mall.com/37653686/the-smart-trick-of-250-hp-electric-outboard-motor-that-nobody-is-discussing