ii. healthy
a. a lot of exercise b. no pollution
iii. personally satisfying a. to enjoy the scenery
iv. conclusion:very pleasurable and helpful ② sentence outline:
thesis: riding a bicycle is of great pleasure i. riding a bicycle is relatively inexpensive a. it is relatively inexpensive to buy a bicycle. b. it is relatively inexpensive to operate a bicycle. ii. riding a bicycle is healthy.
a. riding a bicycle can make us do a lot of exercise
b. riding a bicycle causes no pollution.iii. riding a bicycle is personally satisfying.
a. riding a bicycle can help us enjoy the scenery.
iv. conclusion: riding a bicycle is very pleasurable and helpful. 3、there are four types of english essays: narration（记叙文），description（描写文）， expositon（说明文） and argumentation（议论文）。