选择关联词语填空。

…如果…就……    虽然…但是…

…只要…就……    因为…所以…

①____爸爸看见一棵高大的白杨树身边，几棵小树迎着风沙成长起来，____他的嘴角露出一丝微笑。

②____老象拼命挣扎，并抬头呼救，____还是被陷在淤泥里不能动弹了。

      Yesterday when my son and I were eating dinner, I saw a policewoman walking past our house. A woman with a1look was following her.
      I opened the 2 , went out and asked if everything was OK. The policewoman said that the woman's3 had gone missing(失踪) an hour earlier. I said that we hadn't seen the girl, but wecould4.Iexplained to my son that we couldn't finish our5 right then. He said,” Be a kind person, Dad. "We got in our car and6 the girl all over the town. Along the way,a group of chil­dren were playing.  7they heard what had happened, they said they would help8 . They rode their bikes and joined us. 9 the little girl was found safe a few miles away. I was so 10to see many people help a stranger. It is a nice world.

改革开放是实现中华民族伟大复兴的关键招，是当代中国发展进步的活力之源，是坚持和发展中国特色社会主义的必由之路。

材料一：混合所有制是社会主义初级阶段基本经济制度的重要实现形式。我国经济发展进入新常态，迫切需要将发展动力转换到创新驱动上，深入推进国有企业混合所有制改革，不仅有利于提高国有企业的持续创新能力，而且有利于带动各类非公有制企业特别是民营企业加大研发投入、加快创新步伐，进而放大各自优势，实现良性发展、互促共进。

材料二：2017年5月23日下午召开的中央全面深化改革领导小组第三十五次会议强调指出，试点是重要改革任务，更是重要改革方法。要认真谋划深入抓好各项改革试点，坚持解放思想、实事求是，鼓励探索、大胆实践，敢想敢干、敢闯敢试，多出可复制可推广的经验做法，带动面上改革。

欧洲的人口自然增长率在世界各大洲中居首位。