two structure questions, thanks in advance

brightier

1. The Florida town of seaside (is laid out) on its 80 acres (so) no point is (more than) a 10 or 15 minute (walks) from another.

I know “ walks” is wrong and should be “walk”. But why “ so” is correct? I thought it should be so that.

2.

(The basic) elements of public-opinion (research) are interviewers, questionnaires, tabulating (equipment), and (to sample) population.

I know “ to sample” is wrong and should be “sampling”. But I thought “equipment” is also wrong for it is neither single or plural. Can anybody explain?

Jin_Jin

From p1224- Oxford Advanced Learner's Dictionary (Edited by Sally Wehmeier, OXFORD university press)

Question-1  

So - conj-1,used to show the reason for sth: It was still painful so I went see a doctor.  

Question-2

equipment 不可数名词

ps:语法最好贴到语法区