1 . As a trekker with global footprints, Salopek is committed to experiencing different cultures all over the world and _________ (record) the lives of people he encounters on his journey. (所给词的适当形式填空)

2 . The good news is that Rozier will be back soon after the All-Star break after ________ (sprain) his right knee, but the timeline for Richardson’s return remains unclear.（所给词的适当形式填空）

3 . As for the most suitable means of transportation, I’d like to recommend ______ (take) Beijing-Guangzhou High-Speed Railway. (所给词的适当形式填空)

4 . Our milk powder is especially suitable for children under 6, as it helps a lot to build the body’s natural ________ (defend)．(所给词的适当形式填空)

5 . The country risks ________(upset) the balance of nature by passing a law, which allows cutting down more forests. （所给词的适当形式填空）

6 . Come to Dollywood to have fun ________(learn) all about America’s historical southeastern culture! (所给词的适当形式填空)