Final answer:
The sentence 'Tenemos tantos bolígrafos como ellas' is grammatically correct in Spanish.
Step-by-step explanation:
The sentence 'Tenemos tantos bolígrafos como ellas' is grammatically correct in Spanish. The use of 'tantos' indicates that there is an equal number of pens for both the speaker and the group represented by 'ellas'. The comparative construction 'como ellas' means 'like them'.
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