请大家帮忙看看以下两个句式

1. These students were having academic problems (A) because they spent large amounts of time on school sports and too little time studying (B1) / because of the amount of time they spent on sports (B2).

个人认为： 推理B1/B2->A

2. No students who do well academically spend time on sports.

A: students do well academically B: students do not spend time on sports.

推理：A->B

大家的见解如何呢？