Complex sentence: Tetrahydrocannabinol (THC), often considered to be the primary active substance in cannabis, along with other psychoactive cannabinoids are hydrophobic oils, which are insoluble in water but soluble in lipids (oil/fat) and alcohol.
Split into simpler sentences: Tetrahydrocannabinol (THC) is often considered to be the primary active substance in cannabis. Along with other psychoactive cannabinoids, THC is a hydrophobic oil, which are insoluble in water but soluble in lipids (oil/fat) and alcohol.