Summarization：the paragraph is followed by an incomplete phrase or sentence which summarizes the main idea of the paragraph. Spell out the missing letter of the word on your answer sheet.

Everyone knows that a placebo — a fake medication or sham procedure, typically used as a control in a medical trial — can nonetheless have a positive effect, relieving real symptoms like pain, bloating or a depressed mood. The placebo effect is a result of the patient’s expectation that the treatment will help.
F of a placebo.