Mrs. McTavish looked out. "It's a lovely day. Would you like to go for a walk in the park?" Her children_____（21）with excitement.
"Before we go, you need to follow some rules. Everyone must_____（22）hands and stay close to me. You can't_____（23）anywhere by yourself. Can you all do that?
All four_____（24）they would. As they walked down the street, Fiona said, "I want an ice lolly（冰棍）, Mummy. Can we have some?"
"You can if you follow the rules," answered Mrs. McTavish.
The park is just around the corner. The children ran off to_____（25）. After a while, when Mrs. McTavish looked up she couldn't see Jock. "Fiona, where's Jock?"
“I don't know, Mummy. He's not here_____（26）," said Fiona.
The others hadn't_____（27）Jock either. Mrs. McTavish had to gather her children together and walk around the park_____（28）for him. She found him sitting near the ice lolly man. here? I couldn't_____（29）you."
Mummy, I want an ice lolly," Jock whispered.
"You can't have one now_____（30）you didn't follow the rules." Mrs. McTavish_____（31）one for each of the other children and they licked（舔）them all the way home. Jock cried. When they_____（32）home she talked to Jock. "Mummy has four children. I must have rules so I can_____（33）an eye on you and know you're_____（34）." Jock said he was_____（35）and he would follow the rules from then on.
30._____
A、unless
B、once
C、though
D、because
【正确答案】：D
【题目解析】：逻辑推理题。乔克对妈妈说他想吃冰棍，但是妈妈说乔克现在不能得到一根冰棍，因为他没有遵守妈妈制定的规则。空格前表示的是结果，空格后说明了原因，因此空格处应填入一个表示原因的逻辑连接词。unless除非，表示条件；once一……就，当……时候，表示时间；though虽然，表示让步；because因为，表示原因。故本题选D。
