首先，你应该检查你是否真的在更换Read more, 您还可以删除default: 只需确保返回传递给过滤器的原始值。

如果您特别想使用switch 您可以通过设置switch(true) 然后将if语句括在括号中case

要获取/检查类别，有几种方法可以做到这一点，在下面的示例中，我使用get_the_terms 获取所有类别，然后将所有slug映射到一个数组，以便使用in_array （为了简化示例代码，我删除了其他case语句）：

add_filter( \'woocommerce_product_add_to_cart_text\', \'custom_woocommerce_product_add_to_cart_text\', 10 );

function custom_woocommerce_product_add_to_cart_text( $text ) {

    // First make sure that we are only replacing \'Read more\' as some situations based on product
    // this can be "Select some options" or "Add to cart"
    $wc_read_more = __( \'Read more\', \'woocommerce\' );

    if( $text !== $wc_read_more ){
        return $text;
    }

    global $product;

    $product_type = $product->product_type;
    $product_terms = get_the_terms( $product->ID, \'product_cat\' );

    // Convert to array of all the slugs
    $pc_slugs = array_map( function($term){ return $term->slug; }, $product_terms );

    switch ( true ) {
        case ( $product_type === \'simple\' && in_array( \'services\', $pc_slugs ) ):
            return __( \'Simple text\', \'woocommerce\' );
            break;
    }

    return $text;
}

另一种选择是使用has_term 而不是将段塞映射到阵列：

add_filter( \'woocommerce_product_add_to_cart_text\', \'custom_woocommerce_product_add_to_cart_text\', 10, 2 );

function custom_woocommerce_product_add_to_cart_text( $text, $that ) {

    // First make sure that we are only replacing \'Read more\' as some situations based on product
    // this can be "Select some options" or "Add to cart"
    $wc_read_more = __( \'Read more\', \'woocommerce\' );

    if( $text !== $wc_read_more ){
        return $text;
    }

    global $product;

    $product_type = $product->product_type;

    switch ( true ) {
        case ( $product_type === \'simple\' && has_term( \'services\', \'product_cat\', $product->ID ) ):
            return __( \'Simple text\', \'woocommerce\' );
            break;
    }

    return $text;
}

还想提一下你说的if $product_type = \'simple\' && category = \'services\', 在PHP中，单个= 是赋值，意思是“设置等于”，养成经常使用== 或=== （严格的）即使只是用哀叹的语言解释