It was like a door that had been left open invitingly . Bob stepped through, and immediately regretted it . He was standing in a dim low-ceilinged cave, the walls carved out of solid ice.

    There were five children there ,huddling（拥抱）together in corner ,their eyes fixed hopefully on his . They were dressed exactly as he was ,in pale sheepskin jackets and trousers ,with matching boots ,and caps pulled down over their ears .All of them were in their mid teens, and their faces, pinched（皱缩）as much by fear as with cold , seemed strangely familiar ,as though he had known them all his life . A girl with intense dark eyes nodded towards the end of the room. When he failed to respond, she nodded again , more urgently than before, her lips forming words soundlessly.

    He saw then what he should have seen earlier, a second door set low in the end wall. It was much smaller and far less noticeable than the first ,yet he felt drawn to it just the same . Or was he merely being encouraged by his silent companions? Another of them ,a timid boy, gave him a smile of encouragement, which was instantly reflected in all the other faces .He found it difficult to resist, as if this, after all ,was why he was here to help them out in their mysterious adventure . And under the pressure of their combined request, he bent down and crawled through  the low opening .This time he emerged onto a windswept ledge（岩壁）. Above him, dark grey clouds racked across an even grey sky Below—far below—lay a deserted valley heaped with slabs（厚片）of ice.

1．When Bob entered the cave ,he knew that he           .

    A．was welcome                     

B．was unwelcome

    C．had frightened the children inside                

D．couldn’t leave the cave

2．The children huddled together because they were         .

    A．of one family                    B．trying to keep warm

    C．afraid of Bob                    D．determined to stay together

3．The girl nodded towards the end of the cave because she         .

    A．couldn’t speak Bob’s language 

B．didn’t dare to speak to Bob.

    C．wanted Bob to know their situation                

D．was too hungry to speak

4．Bob went through the second door because       .

    A．the timid boy forced him to do so                 

    B．he found it too cold in the cave

    C．it led to a mysterious unknown place              

    D．the children wanted him to do so