Fill in the blanks with the proper words and expressions given below, change the form where necessary. invisible give identify lonely responsible burden vary express source maintain 1. He is very kind and always ready to me a helpful hand when I’m in trouble. 2. Table manners and eating habits can from country to country. 3. The company has tried to the high quality of their products. 4. I still find it very difficult to myself in English. 5. Most children can their mother by her voice. 6. Over-working can be a on both body and mind. 7. Music is ; we can hear it and feel it, but can not see it. 8. Without friends, he felt in the city he had just arrived in. 9. A group of scientists has set off to look for the of the big river. 10. People have different ideas about who should be for the accident.