#Python 2 - 79 76 75 bytes

x=input()
for i in range(x):print(x-i)*' '+'/----/'+(i*'  '+'\\    \\')[5:]

Thanks to Hubert Grzeskowiak for "disqualifying" me since making my program print actually saved 3 bytes! Thanks also to Eʀɪᴋ ᴛʜᴇ Gᴏʟғᴇʀ for saving 1 more byte!

Python 2 - 79 76 75 bytes

x=input()
for i in range(x):print(x-i)*' '+'/----/'+(i*'  '+'\\    \\')[5:]

Thanks to Hubert Grzeskowiak for "disqualifying" me since making my program print actually saved 3 bytes! Thanks also to Eʀɪᴋ ᴛʜᴇ Gᴏʟғᴇʀ for saving 1 more byte!

#Python 2 - 79 76 bytes

def f(x):
 for i in range(x):print(x-i)*' '+'/----/'+(i*'  '+'\\    \\')[5:]

Thanks to Hubert Grzeskowiak for "disqualifying" me since making my program print actually saved 3 bytes!

#Python 2 - 79 76 75 bytes

x=input()
for i in range(x):print(x-i)*' '+'/----/'+(i*'  '+'\\    \\')[5:]

Thanks to Hubert Grzeskowiak for "disqualifying" me since making my program print actually saved 3 bytes! Thanks also to Eʀɪᴋ ᴛʜᴇ Gᴏʟғᴇʀ for saving 1 more byte!

#Python 2 - 79 bytes

lambda x:'\n'.join((x-i)*' '+'/----/'+(i*'  '+'\\    \\')[5:]for i in range(x))

#Python 2 - 79 76 bytes

def f(x):
 for i in range(x):print(x-i)*' '+'/----/'+(i*'  '+'\\    \\')[5:]

Thanks to Hubert Grzeskowiak for "disqualifying" me since making my program print actually saved 3 bytes!