physically present but mentally somewhere else problem.. use a stopwatch and everytime u lose focus start over and that gives u an idea of the time you able to concentrate and u can push yourself to improve that.. writing something down while reading can also happen when u are thinking about something else and u kept on copying the whole thing again
The 1 st one was best .even I do the same .when u study anything may it be derivation sum or anything, underline the key points and read twice or thrice and then write it down the main points or main step and third while writing it down ,explain it to yourself ki this this is the thing and this happens after that ..and read from 1 same page .bcz when u revise twice finally that page will be printed in your head .and its miracle you'll write smoothly and that page will be reflected in ur mind when u see that question.
And still I'm not figuring out, ki ye ladki hi hain ya ladka? Face bhi similar hain, voice bhi similar hain, personality bhi similar hain, sab similar hain.