In this task, we ask you to rewrite a sentence in simple English without changing its general meaning. Essentially, you want to make the sentence easier to read by using simpler words, utilizing more straightforward sentence structures, and omitting non-essential information etc.
--------
Question: The four temperament theory is a proto-psychological theory which suggests that there are four fundamental personality types : sanguine , choleric , melancholic , and phlegmatic .

Answer: The temperaments are " sanguine " , " choleric " , " melancholy " , and " phlegmatic " .

Question: Commercially , the album was less successful than Madonna 's previous albums , peaking at number 2 on the US " Billboard " 200 , becoming her first studio album not to top the chart since her debut .

Answer: It was less successful than earlier albums by Madonna : it peaked at number two in the United States .

Question: As established by the Mars Exploration Program , the main scientific goals of the MSL mission are to help determine whether Mars could ever have supported life , as well as determining the role of water , and to study the climate and geology of Mars .

Answer:
The main scientific goals of the MSL mission is to search whether Mars could ever have supported life or water and to study the climate and geology of Mars .