捕获单词中包含单引号的字符串

Question

我正在尝试捕获包含3个以上字符的字词，其中包括：我们在字符串中输入，避免，等等。以下内容适用于上述词语。我在这里错过了什么吗？我应该在obj-c中达到nsregularexpressions的限制吗？我应该和NSPredicates一起去吗？

 NSString *currentString = aString;

// Regular expression to find all words that have greater than 3 characters
NSRegularExpression *regex;
regex = [NSRegularExpression regularExpressionWithPattern:@"([\\w\']{4,})"
                                                  options:0
                                                    error:NULL];

NSMutableString *modifiedString = [currentString mutableCopy];
__block int offset = 0;
[regex enumerateMatchesInString:currentString options:0 range:NSMakeRange(0, [currentString length]) usingBlock:^(NSTextCheckingResult *result, NSMatchingFlags flags, BOOL *stop) {
    NSRange range = [result rangeAtIndex:0];
   // NSLog(@"range is %@", NSStringFromRange(range));
    // Adjust location for modifiedString:
    range.location += offset;
    // Get old word:
    NSString *oldWord = [modifiedString substringWithRange:range];
}
 ];