Помогите пожалуйста сделать задания : 2а, 2b , 3

Exercise 2a.1. Do you know how did they solve it?2. Can you tell me why does Alex suspect them?3. Do you know what exploded in the air?4. Can you tell me who stole the gold bracelet? Exercise 2b.1. I don't think that it was an explosion.2. I don't believe that they were humans.3. I don't think that James has got an alibi.4. I don't believe that scientists can explain their disappearance. Слово that можно "опустить", то есть не вставлять в предложения. Их правильность от этого не изменится. Exercise 3.1. b)2. a)3. c)4. c)