Teacher: In this task, you're given an article and an answer. Your task is to generate the fill-in-the-blank question for this answer based on the given article. The blanks are always at the end of the question, and can be filled with more than one word or phrase.
Teacher: Now, understand the problem? If you are still confused, see the following example:
Article: Homework can put you in a badmood , and that might actually be a good thing. Researchers from the University of Plymouth in England doubted whether mood might affect the way kids learn. To find out the answer, they did two experiments with children. The first experiment tested 30 kids. Someshapes were hidden inside a different, larger picture. The kids had to find the small shapes while sitting in a room with either cheerful or sad music playing in the background. To test their mood, the scientists asked the kids to point to one of five faces, from happy to sad. Children who listened to cheerful music tended to point to the smiley faces while the others pointed to the unhappy ones. The researchers found that sad kids took at least a second less to find the small shapes. They also found an average of three or four more shapes. In the second experiment, 61 children watched one of two scenes from a film. One scene was happy, and the other was sad. Just like in the first experiment, kids who saw the sad scene acted better compared to the others. The researchers guessed that feeling down makes people more likely to focus on a problem or difficult situation. Not all scientists agree with them, however. Other studies argued that maybe, that cheerful music in the first experiment distracted kids from finding shapes. While scientists work on finding out the answers, it still might be wise to choose when to do your tasks according to your mood. After eating a delicious ice cream, for example, write an essay.
Answer: whether mood affects their learning ability
Solution: Researchers did experiments on kids in order to find out _ .
Reason: It is clearly mentioned in the article that to the check effect of mood on children is the main purpose of the experiment.

Now, solve this instance: Article: Preface to the fourth edition A practical English Grammar is intended for intermediate and post-intermediate students. We hope that more advanced learners and teachers will also find it useful. The book is a comprehensive survey of structures and forms, written in clear modern English and illustrated with numerous examples. Areas of particular difficulty have been given special attention. Differences between conversational usage and strict grammatical forms are shown but the emphasis is on conversational forms. 1. Explanation and examples have been brought up to date. 2. There is now more information on countable and uncountable nouns, attributive and predicative adjectives, adverbs of places, sentence adverbs, cleft sentences, prepositions, conjunctives, modal verbs, perfect tenses, infinitive constructions, the passive, purpose clauses and nouns. In the fourth edition the main changes are as follows. 3. Some material has been rearranged to make comparisons easier. For example, parts of chapters on can, may, must etc. are now grouped by functions; verbs of liking and preference have a chapter to themselves; suggestions and invitations have joined the chapter on commands, requests and advice. 4. The contents list now summaries every edition heading, and there is a new index containing many more entries references. In this edition the sign "~" is frequently used to show a change of speaker in examples of dialogue. Note also that although the sign "="sometimes connects two words or expressions with the same meaning, it is often used more freely, e.g. to indicate a transformation from active to passive or direct to indirect speech. We wish to thank all at Oxford University Press who have assisted in the preparation of the fourth edition. We would also like to thank Professor Egawa of Nihon University, Japan, Professor Rene Dirven of Duisburg University, West Germany and other colleagues for their friendly and helpful suggestions. London, November 1985 A.J.T., A.VM
Answer: a primary school student
Student:
The grammar book mentioned in this passage is not suitable for _ .