Questions 18 to 20 are based on the following passage. At the end of the passage, you will be given 15 seconds to answer the questions.
______ is the driving force of the formation of a typhoon.

A．until the 1850s.
B．in the late 1700s.
C．well into the 1800s.
D．until nearly 1900.

A．Mr. Lorden’s cello was specially made for him by his uncle.
B．Mr. Lorden got the cello from his uncle.
C．Mr. Lorden has been using the cello since the age of eight.
D．A cello maker gave the cello to Mr. Lorden as a present.