Bilbo used riddling talk with smaug because

a. dragons hate riddles

b. the dwarves told him to

c. he was nervous

d. it is wise not to tell your real name to a dragon

He was nervous

Explanation:

He was nervous because Smaug was a dragon and A dragon is very Dangerous and can harm anybody  including himself. so he used riddling talk to get him not to know much about him and his true intentions

Bilbo used words like : Bilbo Baggins did not come to steal from you , I merely wanted to gaze upon your magnificence to see if what the old tales talk about you is true. all this words were because he was very nervous and was trying to calm Smaug down

a. "to practice" is the best phrase to complete the sentence.

explanation:

during the summer, she likes to practice her soccer skills so that she is ready to play in the fall.

(note that : all the other options "the practicing of", "practice for" and "to do a practice on" are inappropriate as they make the sentence grammatically incorrect.)