You have to be able to differentiate between these words.
But not only by the ear, study them using the buttons and Praat, record your imitation and let yourself decide when you say it right.

• Select the box next to "Keep" so that the words are maintained by the number of times you select in the box next to it.
• With the orange buttons or by clicking on the figures on the right you can hear the pronunciation of the associated word. Remember that the blue line in the figures shows you the place where the vocal cords vibrate. The red ones show you the formants. And the yellow the intensity.
• With the buttons you can watch Youglish.com videos that include the word. Remember the facilities that it offers.
• With the links to Merriam-Webster's, you can verify the word.