• challenge ⪢⪢
A challenge is something difficult to complete
http://qindex.info/i.php?x=13817

• challenge ⪢⪢
It was a challenge to climb to the top of the mountain.
http://qindex.info/i.php?x=13818

○○○ 1962.10.25 ⪢⪢
On October 25th, the blockade was challenged for the first time. Soviet ships approached the quarantine zone but American ships held their ground. The Soviet vessels were forced to turn back and the blockade continued.
http://qindex.info/i.php?x=20292

○○○ give up ⪢⪢
I won't give up my career goals despite the challenges.
http://qindex.info/i.php?x=28869

• Cuba's Geographic Challenge
http://qindex.info/i.php?x=4027

• 01 The Greeks, Newton and Leibniz
○ Many students quit math entirely when they get up to this point, mainly out of fear. ○ We will get to some of those in due time as well. ○ What challenge could possibly have necessitated the development of calculus?
http://qindex.info/i.php?x=5032

Google ➔ Dictionary ➔ Image ➔ YouGlish