【正文】
3. There are some problems which need to be solved.(5 8) A. Radiation. (It is impossible for a car to carry tons of lead in order to prevent the radiation from escaping.) B. The invention of a metal strong enough to hold in the rays and light enough for a car to carry. ( The last sentence in Paragraph 6 lead the readers on the following problems.) is doubtful whether an economic engine could be made. D. The problem of safety. The last paragraph is also the concluding paragraph with the openended question which the author leaves for the reader to answer. Style and Features ? This piece of writing is informal. It is for ordinary readers to read rather than professionals. ? Features 1. The repetition of key ideas, often in slightly different ways. 2. The explanation of some difficult words or phrases by the words that follow them to make the idea stand out very clearly. 3. The use of short sentences for effectiveness. 4. Ef