SN4 ""

No	Pattern	Freq
1	should be [verb] at	505
2	should be [vb pp] at	452
3	should be look at	56
4	should be [v-ing] at	49
5	should be looking at	33
6	should be looked at	22
7	should be make at	20
8	should be made at	20
9	should be do at	17
10	should be done at	16
11	should be taken at	14
12	should be take at	14
13	should be given at	13
14	should be give at	13
15	should be directed at	12
16	should be direct at	12
17	should be set at	10
18	should be set at	10
19	should be avoid at	9
20	should be aim at	9
21	should be avoided at	9
22	should be provide at	8
23	should be provided at	8
24	should be aimed at	8
25	should be hold at	7
26	should be held at	7
27	should be leave at	6
28	should be kept at	6
29	should be consider at	6
30	should be note at	6