When Do We Use Present Perfect?

The correct answer is "has shown" because it indicates that there have been previous studies or research that provide evidence or proof of the positive effects of cycling on patients' recovery from illnesses. Using "has shown" suggests that this is a well-established and supported finding in the scientific community.

The correct answer is "has disappeared" because the phrase "has disappeared" is in the present perfect tense, which is used to talk about actions that started in the past and are still relevant in the present. In this case, the speaker is referring to the current state of their car, which is no longer visible or present.

The correct answer is "has just won." This is because the use of "has" indicates that the action of winning the election happened very recently, and the word "just" further emphasizes the immediacy of the event. Therefore, "has just won" is the most appropriate choice to convey that Mr. Robinson recently achieved victory in the election.

The correct answer is "have washed" because the sentence is in the present perfect tense. The phrase "have washed" indicates that the action of washing the hands was completed in the past and has a connection to the present. This implies that the person has already washed their hands and is now ready to help with the cooking.

The correct answer is "complained". This is because the sentence is in the past tense and does not indicate any ongoing action or connection to the present. Therefore, the simple past tense form of the verb "complain" is the appropriate choice.