1 . Apple is expected to a ________ (宣布) the new iPhone at the conference. （根据中英文提示填空）

2 . Students are encouraged to p________ in a sport by joining a team and taking part in practices and games.

3 . Huawei Research platform wants to partner with professional institutions and consumers to jointly e________(探索) the opportunities for the future. (根据汉语提示单词拼写)

4 . The lifeboat was sent out to r________ the sailors from the sinking ship. (根据首字母单词拼写)