Probiotics<br>My stomach was burning for several days. And I had trouble eating any kind of food. So my dad bought me a probiotic drink made with fermented cabbages. It tasted terrible. But it quickly helped my stomach.
My stomach was upset since last week. 
The test stated several days and not a week. 
( z1 upset :ARG1 ( z2 stomach :part-of ( z3 i ) ) :time ( z4 since :op ( z5 week :mod ( z6 last ) ) ) )