Must или had to?

l forgot to phone Sam yesterday. I ____ phone him today
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I forgot to phone Sam yesterday. I MUST phone him today.

had to используется в времени, а так как у нас указано настоящее [today], то тут подходит только must.

Hello Mike (можешь придумать любое имя)! It’s so great to hear from you! Hope you’re doing well ! In the letter that you’ve send me it said you started playing video games. Here in my country people our age also like to play video games, but they also like to study . For example my best friend Lea , she’s a nerd but loves to play video games with me during her free time. You should visit my country sometimes we could play video games together! As for me I like video games a lot , the first thing I do after my shower before I go to bed , I play video games. But it doesn’t affect my grades. I like role playing games , what about you? About a year ago I didn’t play video game s, because I thought it was a waste of time and boring . Then you introduced me a video game , and it turned out to be really fun and exciting! But I don’t use my computer just for video games I use it for studying as well! What do you use your computer for , except video games? Hope to hear from you soon! Bye Mike!