Find the mistakes
Read this text carefully. In most lines there is one word that should not be there. It is either grammatically incorrect or does not fit in with the sense of the text. Write the extra word in the box after each line. Some lines are correct. If you think there are no incorrect words in a line, write “OK” in the box. Be careful: if a line contains a word that could be removed but it is not incorrect (that is, the sentence is fine if you keep the word), then it is not wrong – you must write OK in the box.
High percentage of US patients on placebos without knowing it.