Playing with toy blocks   may lead to improved language development in young children, a new study reported.      Early childhood is an important period in the development of young minds. The newborn brain grows three times in size between birth and age 2. Scientists have said that certain activities during this important period may promote   healthy development while others may hold it back, and development of memory and language may especially be helped by imaginative play.      After six months, language scores among half of the 175 children aged 1-1/2 to 2-1/2 who were sent plastic blocks were 15 percent higher than a matched group that did not receive the free blocks, according to the study by researchers at the University of Washington in Seattle.     Parents were given ideas about how to help their children play with the blocks, then were told to keep diaries of their children's activities over four days. Finally, all the parents filled out questionnaires that judged their children's vocabulary, grammar, and other language abilities. Study author Dimitri Christakis said unstructured play with blocks motivated children's thinking, memory and physical skills at a time when a child's brain is growing rapidly. "They are the foundation of thought and language," he wrote of the skills learned from building blocks. "Older children begin to make up stories for these objects ." Such play may also take the place of less helpful activities such as watching TV, he said, adding parents ought to have doubts about some toy-makers' words. "An increasing number of media-based products are making ungrounded   claims that they can make children smarter, more literate, and more musical," Christakis said. The aim of the passage is probably to   _  .
raise the present level of children's language ability encourage parents to let their babies play with blocks improve parents' knowledge of raising children encourage makers of blocks to develop more toys