... lam vat hoQc lugn trbn d$ khi budc kh6i bi vip. 2. 2- M$t b@c thang c6 b8n gidng nhrr m$t san : - MQt b@c lang v8a xi milng mac 80- 100 day 20 mm, hay trit granito. De" ch6ng trugt, ... ~4i) c,~, = 43M CTW?~ Gi). T~N A,M, LA; TR~ GM, 423 45 6 I a Ib. 42. A1. 40.g .8 . N&I 6, ddi wbi I e, vdi d A23466 13. 4a. Al. 40.a. 8 4. LA% TA^M V; CUNC B,M* ... ~bu thang vbng ( 2 v6') 9. du thang lech t6hg 10. C6u thang tdn 11. Ca'u thang d6i hdng 1 80° (2 v6 chi& ngh; I/? hi'& trh ) 12. C6u t hang th&g...