Though having failed several times, Tim, who didn’t give up his dream, _____ made his dream come true.

Make sure the gas is turned off after cooking, which would        cause danger to our life.

There was such a long queue for coffee at the interval that we ________ gave up.

When Helen saw his tutor nod ________ to her, she calmed down and went on with her performance. 

Such a problem is＿＿＿＿difficult for a primary school student ＿＿＿.