In the English Grammar Profile, B1 point 37 in the category of PAST/continuous is defined:
give a reason for something, often with ‘because’
PELIC STUDENT EXAMPLE:
I could not focus on my reading at all,
after a while because I was sweating hard.
Chinese male, level 5, writing class
An iWeb search for:
because * _VBD _VVG
1 BECAUSE I WAS TRYING 1574
I only got you those bloody business cards
because I was trying to be cute.
2 BECAUSE I WAS GOING 1560
3 BECAUSE I WAS LOOKING 1317
4 BECAUSE I WAS GETTING 1098
5 BECAUSE I WAS USING 925
6 BECAUSE I WAS THINKING 883
7 BECAUSE I WAS WORKING 766
8 BECAUSE HE WAS GOING 698
9 BECAUSE HE WAS TRYING 558
10 BECAUSE IT WAS GOING 538
11 BECAUSE THEY WERE GOING 517
12 BECAUSE THEY WERE TRYING 510
13 BECAUSE WE WERE GOING 484
14 BECAUSE I WAS FEELING 483
15 BECAUSE IT WAS GETTING 479
16 BECAUSE I WAS PLAYING 444
17 BECAUSE I WAS HOPING 422
18 BECAUSE I WAS RUNNING 382
19 BECAUSE I WAS EXPECTING 340
20 BECAUSE THEY WERE GETTING 333
21 BECAUSE I WAS TAKING 331
22 BECAUSE HE WAS GETTING 328
23 BECAUSE I WAS MAKING 316
24 BECAUSE HE WAS WEARING 308
25 BECAUSE HE WAS PLAYING 284
26 BECAUSE SHE WAS GOING 284
27 BECAUSE I WAS WONDERING 278
28 BECAUSE THEY WERE USING 276
29 BECAUSE THEY WERE LOOKING 271
30 BECAUSE IT WAS RAINING 268
31 BECAUSE HE WAS WORKING 267
32 BECAUSE I WAS WEARING 264
33 BECAUSE HE WAS LOOKING 260
34 BECAUSE SHE WAS TRYING 238
35 BECAUSE I WAS READING 234
36 BECAUSE WE WERE TRYING 232
37 BECAUSE WE WERE GETTING 223
38 BECAUSE I WAS WAITING 221
39 BECAUSE I WAS PLANNING 218
40 BECAUSE WE WERE LOOKING 218
41 BECAUSE IT WAS TAKING 217
42 BECAUSE I WAS STARTING 201
43 BECAUSE IT WAS CAUSING 193
44 BECAUSE SHE WAS WEARING 192
45 BECAUSE HE WAS USING 190
46 BECAUSE I WAS LIVING 189
47 BECAUSE I WAS WATCHING 186
48 BECAUSE THEY WERE WORKING 185
49 BECAUSE WE WERE WORKING 183
50 BECAUSE I WAS EATING 182
51 BECAUSE IT WAS MAKING 173
52 BECAUSE I WAS TALKING 163
53 BECAUSE I WAS WRITING 162
54 BECAUSE WE WERE USING 158
55 BECAUSE HE WAS MAKING 156
56 BECAUSE I WAS SITTING 155
57 BECAUSE THEY WERE PLAYING 151
58 BECAUSE SHE WAS GETTING 150
59 BECAUSE HE WAS TAKING 143
60 BECAUSE I WAS COMING 133
61 BECAUSE I WAS LAUGHING 133
62 BECAUSE HE WAS RUNNING 131
63 BECAUSE THEY WERE MAKING 131
64 BECAUSE THEY WERE TAKING 130
65 BECAUSE HE WAS TALKING 129
66 BECAUSE THEY WERE RUNNING 129
67 BECAUSE I WAS DRIVING 126
68 BECAUSE IT WAS WORKING 126
69 BECAUSE THEY WERE WEARING 124
70 BECAUSE WE WERE PLAYING 124
71 BECAUSE THEY WERE WAITING 121
72 BECAUSE WE WERE RUNNING 121
73 BECAUSE I WAS SEARCHING 120
74 BECAUSE YOU WERE TRYING 120
75 BECAUSE HE WAS SUFFERING 117
76 BECAUSE I WAS MOVING 116
77 BECAUSE WE WERE TALKING 114
78 BECAUSE HE WAS DRIVING 111
79 BECAUSE I WAS SEEING 110
80 BECAUSE I WAS TRAVELING 108
81 BECAUSE I WAS STRUGGLING 105
82 BECAUSE IT WAS BECOMING 103
83 BECAUSE SHE WAS LOOKING 102
84 BECAUSE I WAS LEAVING 99
85 BECAUSE IT WAS TRYING 99
86 BECAUSE HE WAS ACTING 97
And the reason I could trust my competency was because I was acting in service of others.
87 BECAUSE I WAS ENJOYING 97
88 BECAUSE I WAS SPENDING 96
89 BECAUSE YOU WERE GOING 96
90 BECAUSE IT WAS RUNNING 94
91 BECAUSE THEY WERE EXPECTING 94
92 BECAUSE SHE WAS FEELING 92
93 BECAUSE I WAS EXPERIENCING 91
94 BECAUSE I WAS PAYING 90
95 BECAUSE I WAS PUTTING 90
96 BECAUSE HE WAS FEELING 89
97 BECAUSE HE WAS THINKING 88
98 BECAUSE THEY WERE FIGHTING 88
99 BECAUSE SHE WAS WORKING 87
100 BECAUSE I WAS LOSING 86
A2:
becoming, hoping, laughing, losing, moving, spending, trying
B1:
acting, expecting, experiencing, fighting, planning, searching, wondering