Answer and explanation:
There are four verb moods in English: Â indicative, imperative, subjunctive, and interrogative. The interrogative mood is just the verb being used to ask questions.
Suppose one of the mysteries you have wondered about refers to life in other planets. You could ask questions such as:
1. Do aliens look like us?
2. Are there conditions that support life in other planets?
3. Is alien technology more advanced than ours?
4. What are the chances that we'll contact an alien species in the next ten years?
Notice that all we did was transform a regular sentence into a question by adding an auxiliary verb or, in the case of verb to be, placing it before the subject.
