a million things
  一百万件事情”，也就是有很多很多事情的意思。
  It's hard to slow down when you are trying to do a million things.
  当你想要做成百上千件事情的时候是很难慢下来的。
  【类似】I am as busy as a ticking clock.我忙得像滴滴答答的钟。
  be as busy as a bee
  忙忙碌碌，忙死忙活的
  He was as busy as a bee trying to put the house in order.
  他为了要把家里弄得整整齐齐，忙了好一阵子。
  be busy as a beaver
  忙得团团转
  He is working so hard that he is busy as a beaver.
  他没日没夜地，看起来很忙。
  be piled up
  pile up是堆起来,积累，所以如果你想说都堆积如山了，你可以用上这句。
  My work is piled up on my desk.It really makes me crazy!
  我的在我桌上堆满了，真让我抓狂啊!
  be tied up
  被占用，很忙。tie是动词系、绑的意思，被某件事情绑住了，就走不开了咯!
  I'll be tied up the rest of the week,I am afraid.
  这个星期我恐怕都抽不出时间。
  be up to one’s neck
  忙得不可开交
  I can’t possibly come out tonight.I'm up to my neck in work.
  今晚我不可能出来了，我的忙得不可开交。
  have irons in/on the fire
  同时有（很多）事情要做
  Don't have too many irons in/on the fire.
  不要揽太多事。
  in the middle of(doing)sth
  正忙于某事
  I'm in the middle of something.Could you call(me)back later?
  我现在很忙，你能过会儿给我打电话吗?
  not have time to catch one's breath
  忙得连喘口气的功夫都没有，也就是很忙的意思。
  What a day!I don't even have time to catch my breath.
  真糟糕的一天!我甚至连喘气的功夫都没有。
  pressed for time
  没时间，很忙
  If you’re pressed for time,don't forget to relax and take a couple minutes to breathe.
  如果你很忙，也别忘了放松，花几分钟来呼吸一下新鲜空气。
  I am on the trot.
  我非常忙！我十分忙碌！
  trot小跑，on the trot一个接一个。这句话形容一个接一个根本停不下来，十分忙碌。
  I am booked.
  我非常忙！
  booked指预定，我被预定了，比喻异常忙碌。
  I am booked solid all morning.What's up?
  一上午我都有事，怎么了？
  I am on the go.
  我很忙。on the go指忙个不停。
  I got a new job this year where I am on the go all the time.
  我今年找了份新，一直忙得不可开交。
  I am up and doing.
  我非常忙。up and doing忙碌
  I have eggs on the spit.
  我很忙，无暇顾及其他事。
  have eggs on the spit形容手头有事，正在忙着。
  I have my hands full.
  我忙得不得了。（=My hands are full!）
  I mean,I have my hands full right now with family and work.
  我的意思是，现在的和家庭已经让我分身乏术。
  I have only got one pair of hands.
  我非常忙！
  这句话本意是：我只有一双手，意思就是不能做太多的事。本句用于一个人同时被期望或要求做太多事情的时候。
  I am running round in circles.
  我忙得团团转。
  running round in circles非常形象的描述忙的状态。