แก้คำให้ถูกต้อง

HELP TO CORRECT NOW!ไม่ได้แก้ไข

Text from HakanHitit - English

  • The PRESENT PERFECT TENSE and PRES. PERFECT CONTINUOUS TENSE ?

  • 1-I have studied English for 3 weeks by now.
  • 2-I have been studying English for 3 weeks by now.
  • 3-I have studied English often when I was young.
  • 4-I have studied English for many years at university before.

PLEASE, HELP TO CORRECT EACH SENTENCE! - English