Some fans, _____ money was a big problem, could not afford to go to the concert to see their star play.

“The children are playing in the park.”The main structure of the sentence is ______ .

Qian Xuesen tried many times _________ he found thesolution to the puzzle about space technology.

You _________ park here! Look at the sign, it says “No parking”.— Sorry, I didn’t notice that sign just now.

believed that high achievers are ambitious, hardworking, and work toward personal standards of excellence _____ materialrewards．