Good afternoon,

There were few parts in doubt while I was watching the videos for module 4.

article 4-2
3rd paragraph
The sentence “The search for gold expanded to other parts of Australia and, over the next forty years, gold rush fever spread as gold was discovered in various parts of Australia.” 
I translated it as “금의 수색은 호주의 다른 곳 까지 확장되었고, 그 후 40년동안, 호주의 다양한 곳에서 금이 발견되면서 골드러시의 열기가 확산되었다”
I want to know if “그 후 40년 동안” should be in the beginning of the sentence or can just leave it as it is.
 
Also on the 4th paragraph 
“The last big gold rush was the Klondike gold rush in Alaska.”
I translated “마지막 큰 골드러시는 Alaska의 Klondike 골드러시였다.”
because the sentence was in the past tense “was” I translated as -였다. However the lecturer translated 마지막 큰 골드러시는 Alaska의 Klondike 골드러시이다.
Which one is correct?
 
Article 4-3
Starcraft II shakes up S.Korea’s ‘national sport’
I translated “스타크래프트2가 대한민국의 ‘국기’를 개편하다
Is this sentence correct? explanation of the answer wasn’t sufficient in the video.

Thank you!