1、忙于
... be bound for准备到…去；开往 be bound up in热心于；忙于 be bound up with与有密切关系 ...
2、热心于
... mushroom growth迅速发展 be bound up in热心于；专心致志于 be bound up with与……有密切联系 ...
3、对
... at the bottom在底端 be bound up in忙于，对...有兴趣 be bound up with有赖于；与…有关系 ...
4、热衷于
划界，n 跳跃，界限，限制 be bound up in 热衷于，忙于 be bound up with 与…有密切关系 .