SN4 ""

No	Pattern	Freq
61	it is [adj] for	1927
62	it is [verb] for	275
63	it is possible for	256
64	it is possible for	256
65	it is [vb pp] for	204
66	it is important for	191
67	it is important for	191
68	it is [adv] for	185
69	it is difficult for	139
70	it is difficult for	139
71	it is [noun] for	122
72	it is [noun sg] for	117
73	it is necessary for	104
74	it is necessary for	104
75	it is not for	102
76	it is [not/n't] for	102
77	it is time for	92
78	it is time for	92
79	it is good for	91
80	it is not for	91
81	it is easy for	89
82	it is impossible for	88
83	it is impossible for	88
84	it is [adv] for	77
85	it is [adj -er] for	77
86	it is essential for	71
87	it is essential for	71
88	it is common for	61
89	it is common for	61
90	it is [v-ing] for	60