You are right, all are possible. I was thinking... but' Or, " Before I opened the fridge, I thought ..
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
essam gaweesh a, b, c or d
a) thought b) had thought c) was thinkingWhere's d?
They are all correct. I like b well enough. That seems to be your preference. It's fine.
CJ