The development of cameras so small that they can be swallowed by patients ____.

1. have made diagnosing certain diseases much easier

2. has made it much more easier to diagnose certain diseases

3. has made certain diseases much easier to diagnose

4. make diagnosing certain diseases much easier

5. are making it much easier to diagnose certain diseases 

   
   

正确答案如下：

The development of cameras so small that they can be swallowed by patients (has made certain diseases much easier to diagnose)